[main] User input for add/edit screen is lost across process death

[Zhuinden]

Similarly to older issues that have since been either closed or fixed such as #370 and #123 and #731 and #663

This bug seems to have been long-standing, but with MutableStateFlow(UiState) it still persists - as on this screen, SavedStateHandle is used only for transferring screen arguments to the ViewModel, but is not actually used to preserve user inputs across process death.

architecture-samples/app/src/main/java/com/example/android/architecture/blueprints/todoapp/addedittask/AddEditTaskViewModel.kt

Lines 39 to 40 in 7e9d96d

	val title: String = "",
	val description: String = "",

---

On the other hand, TasksViewModel correctly persists the current filter state using savedStateHandle.getStateFlow.

architecture-samples/app/src/main/java/com/example/android/architecture/blueprints/todoapp/tasks/TasksViewModel.kt

Lines 64 to 65 in 7e9d96d

	private val _savedFilterType =
	savedStateHandle.getStateFlow(TASKS_FILTER_SAVED_STATE_KEY, ALL_TASKS)

Filtering state on the tasks screen was originally fixed by setting it on the SavedStateHandle in this commit: cfb5ac6#diff-631edb6efa01767b52856a0e498dc3987e8a2f0e8ba02837377dfbc5684af0cfR111

---

Therefore, AddEdit screen should also correctly save/restore user inputs across process death.