Settings: remove Bluetooth related text from DNS-dialog

* String ´bluetooth_select_a2dp_codec_type_help_info´
   is set on the ´preference_widget_dialog_summary´-dialog
   by default.

Test: make Settings, visual observation
Signed-off-by: Timi Rautamäki <timi.rautamaki@gmail.com>
Change-Id: I6d403f231797bcf5b10bf726cca4e128f4c517ea

src/com/android/settings/network/PrivateDnsModeDialogPreference.java

@@ -189,6 +189,8 @@ public class PrivateDnsModeDialogPreference extends CustomDialogPreferenceCompat
         if (linkInfo.isActionable()) {
             helpTextView.setText(AnnotationSpan.linkify(
                     context.getText(R.string.private_dns_help_message), linkInfo));
+        } else {
+            helpTextView.setText("");
         }
     }