Request hiding IME before starting dismiss biometric UI animation

As recents animation will invoke hideSoftInputFromWindow when the
Biometric UI lost focus during quick-switch.

Since IME hiding animation will be scheduled on the focus app's UI
thread, so if Biometric UI has running the animation on UI thread, the
IME hiding animation will be delayed until the animation finish.

Make sure calling WindowInsetsController#hide(ime()) before starting
dismiss biometric UI to fix this issue.

Fix: 247705580
Test: manual by issue steps:
   1. Unlock the device
   2. Go to Settings -> Network and internet -> Hotspot and tethering
        -> WIFI hotspot
   3. Enable use Wi-Fi hotspot
   4. Tap on Biometric to show keyboard
   5. From password screen go to home screen
   6. Expect keyboard will be hidden without being delayed
Change-Id: I541f41832753ea1f4f48f6c4745649606b37d207