Add new field is_meta_ct field to v1/installs for Meta Install Referrer

[nsingh-branch]

Description

The server actually needs to know if a Meta Install Referrer was a click-through or view-through, so we need to pass it through in the install request. To do this, we create a new field in install requests called is_meta_ct. It will only be included in installs where a Meta Install Referrer is being attached as well.

Testing Instructions

Check that the field is being included in the request only when necessary and accurately. Also ensure no other logic is being broken by this change.

Risk Assessment [LOW]

• [x] I, the PR creator, have tested — integration, unit, or otherwise — this code.

Reviewer Checklist (To be checked off by the reviewer only)

• [ ] JIRA Ticket is referenced in PR title.
• Correctness & Style
  • [ ] Conforms to AOSP Style Guides
  • [ ] Mission critical pieces are documented in code and out of code as needed.
• [ ] Unit Tests reviewed and test issue sufficiently.
• [ ] Functionality was reviewed in QA independently by another engineer on the team.

cc @BranchMetrics/saas-sdk-devs for visibility.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 16.66667% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 38.04%. Comparing base (53e1788) to head (465a120).

:exclamation: Current head 465a120 differs from pull request most recent head cb0a21e. Consider uploading reports for the commit cb0a21e to get more accurate results

Files	Patch %	Lines
...a/io/branch/referral/ServerRequestInitSession.java	0.00%	4 Missing :warning:
...K/src/main/java/io/branch/referral/PrefHelper.java	0.00%	3 Missing :warning:
...main/java/io/branch/referral/AppStoreReferrer.java	0.00%	2 Missing :warning:
...c/main/java/io/branch/referral/SystemObserver.java	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1174 +/- ## ============================================ - Coverage 38.08% 38.04% -0.04% Complexity 686 686 ============================================ Files 59 59 Lines 6270 6279 +9 Branches 937 939 +2 ============================================ + Hits 2388 2389 +1 - Misses 3436 3444 +8 Partials 446 446 ```

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