Move TEST_HARNESS_TRIGGER_TIMEOUT to MotionPauseDetector directly

- Removed TestProtocol.sForcePauseTimeout and
  TestProtocol.REQUEST_SET_FORCE_PAUSE_TIMEOUT
- Instead, add MotionPauseDetector.TEST_HARNESS_TRIGGER_TIMEOUT, which
  is used when Utilities.IS_RUNNING_IN_TEST_HARNESS.

Test: unbundled/launcher/launcher3_test_platform
Fixes: 232548865
Change-Id: I224e99042b41375cab6bffd555434217518958c5