Replace limited connectivity notification after detecting it

No internet notification may be prompted before partial
connectivity being detected. Partial connectivity status will
be set into NAI and prompted in the Setting. Behavior is not
aligned between Setting and notification. Thus, update
notification again if partial connectivity is detected.
Also, sliently show the updated notification if no internet
notification has already been shown to user to prevent alerting
user in short time.

Bug: 130683832
Test: Verified with simulated partial connectivity
Test: atest FrameworksNetTests
Change-Id: Ie16a8ce6e0fa437048e8c1eea240314ca30e9520