Prevent FGS notification from exceeding allowed

As only the FGS flag is removed by removeForegroundServiceFlagFromNotification,
it exceeds the package limit(MAX_PACKAGE_NOTIFICATIONS).
And eventually OutOfMemory occurs and the device is reset.
When the flag is removed, check in the same way the normal notification to prevent problems.

Test: Searching for images in the Chrome browser
Test: Download more than 50 images
Test: Check NotificationRecord count in Notification dump
Change-Id: Iacbc3a3e545f62d15bae5245ebcf6ed47f5c83a8