Messaging: Fix modifiers

We either have too few or too many

Change-Id: I09a9a38b859c68526fcbcdbc7862afe1d693f6c0

src/com/android/messaging/ui/conversation/ConversationInput.java

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 The Android Open Source Project
+ * Copyright (C) 2024 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,7 +37,7 @@ public abstract class ConversationInput {
     }
 
     protected boolean mShowing;
-    protected ConversationInputBase mConversationInputBase;
+    protected final ConversationInputBase mConversationInputBase;
 
     public abstract boolean show(boolean animate);
     public abstract boolean hide(boolean animate);