Braille: Allow quick USB connections in SUW

This CL sets up a USB listener in the Accessiblity Service to
automatically grant permission for Braille devices to use TalkBack.

Bug: b/420461857
Test: AccessibilityServiceConnectionTest
Flag: com.android.server.accessibility.enable_braille_suw_immediate_connections
Change-Id: I4703981a1fbd9249ef6d51c864b355ba7ce8bf83