Fixes #3922: Added accessibility announcement for history empty state.

Sent an announcement when the list becomes empty in order to tell the user
that there is no history.

app/src/main/java/org/mozilla/fenix/library/history/HistoryView.kt

@@ -107,6 +107,9 @@ class HistoryView(
     fun updateEmptyState(userHasHistory: Boolean) {
         history_list.isVisible = userHasHistory
         history_empty_view.isVisible = !userHasHistory
+        if (!userHasHistory) {
+            history_empty_view.announceForAccessibility(context.getString(R.string.history_empty_message))
+        }
     }
 
     override fun onBackPressed(): Boolean {