- Filter out unnecessary onSwitchChanged callbacks when the switch is
disabled, which should not be triggered by user input.
- Refine the state handling function to avoid unnecessary
onSwitchChanged callback.
- Refine the error handling of isHotspotPasswordValid function.
Bug: 227719584
Test: manual test
make RunSettingsRoboTests \
ROBOTEST_FILTER=WifiTetherSwitchBarControllerTest
Change-Id: If62aaadc8ddb214769b1367d7801b6125bb5377c