Get long press timeout directly

GestureDetector is preloaded by Zygote so the value of constant
would be init at early stage of boot. Since the value needs to
change dynamically, get timeout directly. Bedides, keeping get
the current value from core setting instead of setting provider
directly to reduce disk I/O.

Bug: 112929201
Test: a11y CTS & unit test
Change-Id: Iaaad801baabab90732dabbf17399dee2c0eec04b