Fix NPE crash in UwbPreferenceController and optimize the lifecycle observer adding condition in page

This patch contains two fixes:

- Make sure mUwbManager is non-null by calling isUwbSupportedOnDevice to avoid a NPE.
- Modify AdvancedConnectedDeviceDashboardFragment, add lifecycle observer only if device supports UWB.

Bug: 244871579

Test: manual test and Robotest.
Change-Id: I78f97794a66f3fb487f067c4570899e21c254acf
2 files changed