bug(ios): fickle iOS unit tests

**Describe the bug**
From #4694:

> Verify that all unit tests for iOS are currently passing. (Newly added for 14.0)
>
>> There seems to be a bit of instability with two unit tests: `testCancellationWithAssociations` and `testFickleSelection`.
>> They usually pass, but may occasionally fail during test runs.
>>
>> - `testCancellationWithAssociations` seems to only fail on the initial run of a test suite after its 'host app' has been installed. Re-runs won't fail - it's just the first run.
>> - So, while fine for now... it'll definitely need to be fixed whenever we integrate the unit tests into iOS's CI.
>> - `testFickleSelection` interestingly only fails for the inProgress case, which is fortunately not actually used within the iOS app.

**To Reproduce**
Noted in the quote above, actually. They also seem to fail more consistently when doing a run of the full suite, rather than individually.

**Expected behavior**
They're unit tests. They should pass consistently.

**Other details**
I remember more of the tests having gone fickle when moving from Xcode 11.4 to Xcode 12. The others have been fixed since I made that transition, but the whole "Xcode 12" thing may matter.