Fix FAB visibility after SearchView dismissal on deck deletion

Fixes bug in DeckPicker:
open toolbar SearchView -> FAB is hidden -> long click deck ->
delete deck -> Info SnackBar appears, SearchView is closed, FAB is still missing

Deleting the deck would refresh the menu so the SearchView gets
rebuilt and its listeners(which handle the FAB) would not get triggered.

The fix sets the the FAB as visible when the delete deck handler is hit, just
before the SnackBar is requested.

Author: lukstbit

AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt

@@ -610,6 +610,7 @@ open class DeckPicker :
     @Suppress("UNUSED_PARAMETER")
     private fun setupFlows() {
         fun onDeckDeleted(result: DeckDeletionResult) {
+            floatingActionButtonBinding.fabMain.isVisible = true
             showSnackbar(result.toHumanReadableString(), Snackbar.LENGTH_SHORT) {
                 setAction(R.string.undo) { undo() }
             }