[Physical Keyboard] Update Input Setting Dialog

1. update button style to use custom one
2. use scrollview so it won't be truncated in shorter screen

Bug:389973784
Flag: com.android.settings.keyboard.keyboard_and_touchpad_a11y_new_page_enabled
Test: atest
packages/apps/Settings/tests/robotests/src/com/android/settings/inputmethod/

Change-Id: I57765e88751b6090606d56bbe2335813ef7fd2fc