Fix ServiceConnectionLeaked error.

When activity destroyed, not unbind the service, error occurred.

Test: Manual

Change-Id: I3636f31eda2a6618fd4820c2d0a890170eb08f81
Signed-off-by: Wang Xin <jeamotu@gmail.com>
diff --git a/src/com/android/car/dialer/TelecomActivity.java b/src/com/android/car/dialer/TelecomActivity.java
index 06d74da..6738d04 100644
--- a/src/com/android/car/dialer/TelecomActivity.java
+++ b/src/com/android/car/dialer/TelecomActivity.java
@@ -102,6 +102,7 @@
             Log.d(TAG, "onDestroy");
         }
         mUiBluetoothMonitor.tearDown();
+        mUiCallManager.tearDown();
         mUiCallManager = null;
     }