Adds ENABLE_SEARCH_HAPTIC_COMMIT feature flag.

This controls whether a haptic is played when search invocation
starts. The assumption is that the search app will play this
haptic if the flag is disabled (default).

Test: Manual
Bug: 310659178
Bug: 314005577
Flag: LEGACY ENABLE_SEARCH_HAPTIC_COMMIT DISABLED
Change-Id: I406c18cfaf27d004e19de26f00c997c0a03de996