Update flags on the window to allow the window to be focusable.

This fixes the issue of IME (soft keyboard) not showing up when the compose password bouncer is enabled.
InputMethodManager doesn't show the IME when the window containing the text field has the FLAG_NOT_FOCUSABLE flag.

Fixes: 361793239
Test: manually,
 1. set password auth method
 2. open the bouncer
 3. keyboard should show up
Flag: com.android.systemui.compose_bouncer
Change-Id: I665d57c80f9ea9922803f81a987ec5f61e0bd6c4