fix translation of MessageDetailsActivity's label

Fixes #2875
Closes #3050

//FREEBIE

src/org/thoughtcrime/securesms/MessageDetailsActivity.java

@@ -105,6 +105,7 @@ public class MessageDetailsActivity extends PassphraseRequiredActionBarActivity
     super.onResume();
     dynamicTheme.onResume(this);
     dynamicLanguage.onResume(this);
+    getSupportActionBar().setTitle(R.string.AndroidManifest__message_details);
   }
 
   private void initializeResources() {