hide button when scrolling to unread mention

Signed-off-by: sowjanyakch <sowjanya.kch@gmail.com>

app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt

@@ -1043,6 +1043,7 @@ class ConversationsListActivity :
                 nextUnreadConversationScrollPosition,
                 binding.recyclerView.height / OFFSET_HEIGHT_DIVIDER
             )
+            binding.newMentionPopupBubble.visibility = View.GONE
         }
         binding.newMentionPopupBubble.let { viewThemeUtils.material.colorMaterialButtonPrimaryFilled(it) }
     }