Allow deleting 7 messages at a time permanently

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

@@ -335,7 +335,7 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
     private NumberFormat NF = NumberFormat.getNumberInstance();
 
     private static final int MAX_MORE = 100; // messages
-    private static final int MAX_PERMANENT_DELETE = 3; // messages
+    private static final int MAX_PERMANENT_DELETE = 7; // messages
     private static final int MAX_SEND_RAW = 50; // messages
     private static final int SWIPE_DISABLE_SELECT_DURATION = 1500; // milliseconds
     private static final float LUMINANCE_THRESHOLD = 0.7f;