adapter: avoid blinking messages

Change-Id: Ia0b9b74dd38fa352f7d5c95125b7f591bf4c9d45

ring-android/app/src/main/java/cx/ring/adapters/ConversationAdapter.kt

@@ -206,7 +206,7 @@ class ConversationAdapter(
      * Updates the contact photo to use for this conversation
      */
     fun setPhoto() {
-        notifyDataSetChanged()
+        //notifyDataSetChanged()
     }
 
     override fun getItemCount(): Int {