Fix false-positive matching of notification to FGS

A combination of "uninitialized == 0 which is a valid and commonly used
notification ID" with an incomplete check for "FGS with this
notification."

Bug: 189990824
Test: atest CtsAppTestCases:android.app.cts.ServiceTest
Test: atest CtsAppTestCases:android.app.cts.NotificationManagerTest
Change-Id: I845600325c4098e6b6af2f038de4c7aac9899694
1 file changed