Handle juniper devices that do not have an yellow/red alarm count

[johannaengland]

First step to #212.

This will make the task do nothing in case we get a NoSuchNameError from snmp.get and also do nothing in case the results are both falsy values that aren't int (None or ""). This avoids a lot of error logging in case we have juniper devices that do not have yellow/red alarm counts.

The rest of the issue needs to be fixed within the snmp module, such that when the object is not available an NoSuchNameError should be thrown.

[github-actions[bot]]

Test results

    3 files      3 suites   51s :stopwatch: 319 tests 319 :heavy_check_mark: 0 :zzz: 0 :x: 957 runs  955 :heavy_check_mark: 2 :zzz: 0 :x:

Results for commit 86a06a70.

:recycle: This comment has been updated with latest results.

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.97%. Comparing base (e81e7ed) to head (a65d962).

:exclamation: Current head a65d962 differs from pull request most recent head b087b4e

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #231 +/- ## ========================================== - Coverage 98.98% 98.97% -0.01% ========================================== Files 50 50 Lines 6570 6573 +3 ========================================== + Hits 6503 6505 +2 - Misses 67 68 +1 ```

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Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

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