bring back the ripple when clicking on preview

Closes #4506
// FREEBIE

res/layout/conversation_list_item_view.xml

@@ -83,7 +83,7 @@
                 app:backgroundColorHint="?conversation_background"
                 android:visibility="gone"
                 tools:src="@drawable/ic_video_light"
-                tools:visibility="visible"                />
+                tools:visibility="visible" />
 
         <TextView android:id="@id/date"
                   android:layout_marginLeft="3dip"

src/org/thoughtcrime/securesms/ConversationListItem.java

@@ -94,13 +94,7 @@ public class ConversationListItem extends RelativeLayout
     this.dateView          = (TextView)        findViewById(R.id.date);
     this.contactPhotoImage = (AvatarImageView) findViewById(R.id.contact_photo_image);
     this.thumbnailView     = (ThumbnailView)   findViewById(R.id.thumbnail);
-
-    this.thumbnailView.setOnClickListener(new View.OnClickListener() {
-      @Override
-      public void onClick(View v) {
-        ConversationListItem.this.performClick();
-      }
-    });
+    thumbnailView.setClickable(false);
   }
 
   public void set(@NonNull MasterSecret masterSecret, @NonNull ThreadRecord thread,