Add the RequiresPermission annotation to UsageStats APIs.

Some of the APIs in UsageStatsManager required the PACKAGE_USAGE_STATS
permission but not all of them had the annotation.

Bug: 406803060
Test: atest CtsUsageStatsTestCases
Flag: EXEMPT updating annotations only
FCRS_CODE : malxkhopqhlpvj

Change-Id: I0688eefcb7f72b8277fdb923978b38ed542eacf7