Revert "Action bar is necessary now"

This reverts commit 41bd388aa8.

app/src/main/java/eu/faircode/email/ApplicationEx.java

@@ -247,8 +247,6 @@ public class ApplicationEx extends Application {
             if (!prefs.contains("poll_interval"))
                 editor.putInt("poll_interval", 0);
             editor.remove("first");
-        } else if (version < 999) {
-            editor.remove("actionbar");
         }
 
         if (BuildConfig.DEBUG && false) {

app/src/main/res/layout/fragment_options_display.xml

@@ -730,7 +730,6 @@
             android:layout_marginTop="12dp"
             android:checked="true"
             android:text="@string/title_advanced_actionbar"
-            android:visibility="gone"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/swSeekbar"