For #12971 - Show collection saved snackbar above FAB (#16311)

app/src/main/java/org/mozilla/fenix/tabtray/TabTrayDialogFragment.kt

@@ -70,7 +70,12 @@ class TabTrayDialogFragment : AppCompatDialogFragment(), UserInteractionHandler
     private lateinit var tabTrayDialogStore: TabTrayDialogFragmentStore
 
     private val snackbarAnchor: View?
-        get() = if (tabTrayView.fabView.new_tab_button.isVisible) tabTrayView.fabView.new_tab_button
+        get() = if (tabTrayView.fabView.new_tab_button.isVisible ||
+                    tabTrayView.mode != Mode.Normal) tabTrayView.fabView.new_tab_button
+        /* During selection of the tabs to the collection, the FAB is not visible,
+           which leads to not attaching a needed AnchorView. That's why, we're not only checking, if it's not visible,
+           but also if we're not in a "Normal" mode, so after selecting tabs for a collection, we're pushing snackbar
+           above the FAB, as we're switching from "Multiselect" to "Normal". */
         else null
 
     private val collectionStorageObserver = object : TabCollectionStorage.Observer {