Add Instant hotspot preference

- Add Instant hotspot preference to Wi-Fi hotspot settings

- Wait onServiceConnected callback and then getSettingsState

- Use the PendingIntent provided by SharedConnectivitySettingsState to launch Instant hotspot settings

Bug: 268550769
Test: manual test
atest -c WifiTetherSettingsTest
atest -c WifiTetherViewModelTest \
         SharedConnectivityRepositoryTest

Merged-In: I343599e6127d9b1cb4af661dcc80a8683589c7b8
Change-Id: I343599e6127d9b1cb4af661dcc80a8683589c7b8