camera:fix wait request timeout in switching camera

This issue happened from two camera apps switch each other which is based on api1.In apil need do the syncwithDevice to wait the mLatestRequestsignal.In the switch case, exist prepareHalRequests return an error flags, then exit the request loop without signal mLatestRequestsignal.So it caused the app which use api1 syncwithDevice timeout.So resolution is add codes to signal mLatestRequestsignal during the last requstloop exit.It should not block the next app start.

Bug：312989788
Test: Stress test for open/close camera from different camera app

Change-Id: Iea45693fe654532f0174f50f87bc114ad2c2321b
Signed-off-by: chenguolin <chenguolin@xiaomi.corp-partner.google.com>