Preparation for adding a SHORT_SERVICE timeout

Step 1:
- Adding one more device_config constant
- Added IApplicationThread callback for Service.onTimeout.

Bug: 257270313
Test: Build & Boot
Test: `dumpsys activity settings | grep -i short` and check short_fgs_proc_state_extra_wait_duration
Test: `device_config put activity_manager short_fgs_proc_state_extra_wait_duration 4` and check the above dumpsys
Change-Id: I1910b900232ed57fc6b68f1197770a1e646ba52b