Enable on-screen keyboard for 3P remote/keyboard

Currently on-screen keyboard doesn't get shown if the framework detects
an input device with an alphabetical keyboard. Unfortunately, many 3P
BLE input devices without alphabetical keyboards get wrongly recognized
as an alphabetical keyboard, which results in a problematic UX where a
user is unable to enter necessary inputs.

Bug: 164199939
Bug: 156669963

Test: adb shell settings get secure show_ime_with_hard_keyboard
Change-Id: Ic7a50c0e6d041568c85e22528ce9b7d472b260db