fix(DataStore): Add 'weak self' to prevent retain cycles in OutgoingMutationQueue

[lawmicha]

Issue #

#3325

Description

The crash in the issue above points to OutgoingMutationQueue.swift:142

self.operationQueue.isSuspended = false

In this PR, we're addressing strong reference cycles in OutgoingMutationQueue by adding weak self. Calls to Amplify.DataStore.stop() will deintialize RemoteSyncEngine, which holds a single instance of the OutgoingMutationQueue. It's likely that OutgoingMutationQueue (self) is deallocated before one of the closures that have strong reference to self is executed. Then later, when it executes, it tries to access the deallocated self and crashes

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (0211104) 68.09% compared to head (29180f4) 68.09%.
Report is 5 commits behind head on main.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3429   +/-   ##
=======================================
  Coverage   68.09%   68.09%           
=======================================
  Files        1086     1086           
  Lines       36304    36306    +2     
=======================================
+ Hits        24721    24724    +3     
+ Misses      11583    11582    -1     

Flag	Coverage Δ
API_plugin_unit_test	67.07% <ø> (ø)
AWSPluginsCore	64.38% <ø> (ø)
Amplify	48.17% <ø> (-0.02%)	⬇️
Analytics_plugin_unit_test	81.16% <ø> (ø)
Auth_plugin_unit_test	79.07% <ø> (ø)
CoreMLPredictions_plugin_unit_test	59.44% <ø> (ø)
DataStore_plugin_unit_test	80.95% <100.00%> (+0.03%)	⬆️
Geo_plugin_unit_test	70.75% <ø> (ø)
Logging_plugin_unit_test	63.09% <ø> (ø)
Predictions_plugin_unit_test	37.29% <ø> (ø)
PushNotifications_plugin_unit_test	87.03% <ø> (ø)
Storage_plugin_unit_test	78.10% <ø> (ø)
unit_tests	68.09% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.