[CM] Fix NPE due to unvalidated callback value

Fix flaky test resulting from the above fix.

Bug: 132950880
Fix: 133457081
Test: atest ConnectivityServiceTest
Merged-In: Ia2cc04b42288ea987483e5ab0e0a10093dc49502
Change-Id: Ia2cc04b42288ea987483e5ab0e0a10093dc49502
(cherry picked from commit 9869b47cc2a62c92b13f1aaba77fe6d063291fc1)
1 file changed