Fix show/hide virtual keyboard delay

The default observer delay is 10s for background
service. When a device connected to a hardware
keyboard, the delay makes soft keyboard visibility
is unsync after user switch the configuration.

Notify the SHOW_IME_WITH_HARD_KEYBOARD change
without delay.

Bug: 240210005
Test: Manual with bug steps
Change-Id: I7f8cb0df514fdea4ed0e092cd4466931ec200969