Fix offline areas crash

[andreia-ferreira]

Fixes #3407

When downloading 2 offline areas in a row, the app would crash. This is because the OfflineAreaSelectorViewModel was annotated with @SharedViewModel, which meant that the navigate SharedFlow outlived the fragment and, when a new OfflineAreaSelectorFragment was created, it reuses the previous VM. Then, on emiting a navigate event, it was collected twice: the current fragment and the one in the backstack - the one which crashed, because the navigation was already on the home screen.

This PR removes the @SharedViewModel usage from that VM, since it's only used by a single fragment anyway. Additionally, the flow collectors in the fragment were refactored to prevent memory leaks (using the viewlifecycle owner to launch coroutines and repeatOnLifecycle(Lifecycle.State.STARTED))

@shobhitagarwal1612 PTAL?

[codecov]

Codecov Report

❌ Patch coverage is 67.04545% with 29 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.07%. Comparing base (9868ea3) to head (f7a3bbf).

Files with missing lines	Patch %	Lines
...flineareas/selector/OfflineAreaSelectorFragment.kt	30.00%	20 Missing and 8 partials ⚠️
...lineareas/selector/OfflineAreaSelectorViewModel.kt	96.87%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3660      +/-   ##
============================================
+ Coverage     66.80%   67.07%   +0.26%     
- Complexity     1608     1611       +3     
============================================
  Files           363      363              
  Lines          8980     8983       +3     
  Branches       1159     1162       +3     
============================================
+ Hits           5999     6025      +26     
+ Misses         2332     2306      -26     
- Partials        649      652       +3     

Files with missing lines	Coverage Δ
...neareas/selector/model/OfflineAreaSelectorEvent.kt	100.00% <100.00%> (ø)
...neareas/selector/model/OfflineAreaSelectorState.kt	100.00% <100.00%> (ø)
...lineareas/selector/OfflineAreaSelectorViewModel.kt	88.42% <96.87%> (+23.52%)	⬆️
...flineareas/selector/OfflineAreaSelectorFragment.kt	45.71% <30.00%> (-4.94%)	⬇️

... and 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[shobhitagarwal1612]

Can we combine all separate mutable states to a single UiState?

[andreia-ferreira]

@shobhitagarwal1612 fully agree! I've refactored the VM to unify the overall state under OfflineAreaSelectorState and one time events with OfflineAreaSelectorEvent. Ready for another look