Avoid UI freezing when reading battery capacity/status

Reading battery capacity and status could fail and end up
with timeout after 5s for some input devices, for example:
8BitDo SN30 Pro+ gamepad.

Before reading those items, it would be better to release
`mLock` so that other threads could run.

Bug: 244088945
Test: Manually verified no UI freezing when calling
  `inputDevice.batteryState.capacity` or
  `inputDevice.batteryState.status`

Change-Id: Ibb6b8c999b7fd4fe7fbcc57264a1fe6ad74903dc