1. Remove the placeholder summary so it won't show blank summary
2. Update settings_entity_header to make text center_vertical,
so it could align with the icon.
Bug: 71742145
Test: Screenshot
Change-Id: I185114a4e0c8d996f218075a8633e802fabf3c66
Then UI won't be janky(as everything slide down a little bit)
Bug: 63910184
Test: RunSettingsRoboTests
Change-Id: Ie4074694f54af92da52f09d2caaab5490fa73647
The core thing is to find out a way to update group when devices
(bt device and usb device)are updated.
The infrastructure contains three parts:
1. ConnectedDeviceController
Normal PreferenceController. Get info from sub controller and update
the preferenceGroup.
2. BluetoothDeviceUpdater
Listen to bluetooth callback, decide whether to add/remove devices
3. DevicePreferenceCallback
Interface to add/remove preference. This interface will be used in
ConntectedDeviceController and future SavedDeviceController
Bug: 69333961
Test: RunsettingsRoboTests
Change-Id: I85a9ef216a801d5f0dd1cf0130d53850a68be4bd
