MainFragment: Use different pairing button label when connected.

app/src/main/java/de/ccc/events/badge/card10/main/MainFragment.kt

@@ -76,6 +76,7 @@ class MainFragment : Fragment() {
     private fun showConnectedView(view: View) {
         view.findViewById<ConstraintLayout>(R.id.container_connected).visibility = View.VISIBLE
         view.findViewById<ConstraintLayout>(R.id.container_disconnected).visibility = View.GONE
+        view.findViewById<Button>(R.id.button_pair).text = getString(R.string.main_button_manage_pairings)
     }
 
     private fun showDisconnectedView(view: View) {