Added Null check to prevent crash for TrailHead Go Android

[umashankar-sf]

com.salesforce.trailheadgo.app_issue_fa4327a6a3154091d49279fa5eba233c_crash_session_6722C99202280001286FF83BCF5223CF_DNE_0_v2_stacktrace.txt

https://console.firebase.google.com/project/trailhead-go/crashlytics/app/android:com.salesforce.trailheadgo.app/issues/3acb1308797bc3f5179c50ae5d9d0335?time=last-ninety-days&types=crash&versions=4.1.1%20(4)%20(4010101)&sessionEventKey=672B3B16020000015F77FD9E92962BED_2012546185538799571

https://console.firebase.google.com/project/trailhead-go/crashlytics/app/android:com.salesforce.trailheadgo.app/issues/fa4327a6a3154091d49279fa5eba233c?time=last-ninety-days&types=crash&versions=4.1.1%20(4)%20(4010101)

[salesforce-cla[bot]]

Thanks for the contribution! It looks like @umashankar-sf is an internal user so signing the CLA is not required. However, we need to confirm this.

[mobilesdk-bot]

	1 Warning
:warning:	No Lint Results.

Tests results for SalesforceSDK

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[mobilesdk-bot]

	1 Warning
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Tests results for SmartStore

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[mobilesdk-bot]

	1 Warning
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Tests results for SalesforceHybrid

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Tests results for MobileSync

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[mobilesdk-bot]

	1 Error
:no_entry_sign:	Tests have failed, see below for more information.

	1 Warning
:warning:	No Lint Results.

Tests:

Name	Classname	Time
test[testCleanResyncGhosts]	com.salesforce.androidsdk.reactnative.ReactMobileSyncTest	132.474

Tests results for SalesforceReact

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 58.82%. Comparing base (8a67d31) to head (2d8a8c0). Report is 5 commits behind head on dev.

Files with missing lines	Patch %	Lines
.../com/salesforce/androidsdk/rest/ClientManager.java	0.00%	1 Missing and 1 partial :warning:
...m/salesforce/androidsdk/security/AppLockManager.kt	0.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #2633 +/- ## ============================================ - Coverage 58.93% 58.82% -0.12% + Complexity 2456 2450 -6 ============================================ Files 189 189 Lines 15475 15477 +2 Branches 1998 2000 +2 ============================================ - Hits 9120 9104 -16 - Misses 5426 5439 +13 - Partials 929 934 +5 ``` | [Flag](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | Coverage Δ | | |---|---|---| | [MobileSync](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | `82.02% <ø> (ø)` | | | [SalesforceHybrid](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | `57.36% <ø> (ø)` | | | [SalesforceReact](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | `51.38% <ø> (-0.98%)` | :arrow_down: | | [SalesforceSDK](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | `45.02% <0.00%> (-0.14%)` | :arrow_down: | | [SmartStore](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | `78.31% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files with missing lines](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom) | Coverage Δ | | |---|---|---| | [...m/salesforce/androidsdk/security/AppLockManager.kt](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633?src=pr&el=tree&filepath=libs%2FSalesforceSDK%2Fsrc%2Fcom%2Fsalesforce%2Fandroidsdk%2Fsecurity%2FAppLockManager.kt&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom#diff-bGlicy9TYWxlc2ZvcmNlU0RLL3NyYy9jb20vc2FsZXNmb3JjZS9hbmRyb2lkc2RrL3NlY3VyaXR5L0FwcExvY2tNYW5hZ2VyLmt0) | `96.96% <0.00%> (-3.04%)` | :arrow_down: | | [.../com/salesforce/androidsdk/rest/ClientManager.java](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633?src=pr&el=tree&filepath=libs%2FSalesforceSDK%2Fsrc%2Fcom%2Fsalesforce%2Fandroidsdk%2Frest%2FClientManager.java&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom#diff-bGlicy9TYWxlc2ZvcmNlU0RLL3NyYy9jb20vc2FsZXNmb3JjZS9hbmRyb2lkc2RrL3Jlc3QvQ2xpZW50TWFuYWdlci5qYXZh) | `45.02% <0.00%> (-0.40%)` | :arrow_down: | ... and [3 files with indirect coverage changes](https://app.codecov.io/gh/forcedotcom/SalesforceMobileSDK-Android/pull/2633/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=forcedotcom)