Fix deadlock between DPMS and AMS

Fixing deadlock between DevicePolicyManagerService and
AccessibilityManagerService.

(HOLD_AMS_LOCK)AMS.isAccessibilityTargetAllowed - > DPMS.getPermittedAccessibilityServicesForUser(WAIT_FOR_DPMS_LOCK)

(HOLD_DPMS_LOCK)DPMS.dump -> AMS (WAIT_FOR_AMS_LOCK)

Bug: 284777986
Test: NA
Change-Id: I0aa2e397ac49d90b5f89ba10e11cab665cc2e915