clearCallingIdentity before calling into getPackageUidAsUser

Fix: 70585244
Bug: 69981755

Test: Enable any accessibility service -> inflate work profile
      -> Tap on any work app -> no longer crash

Test: cts-tradefed run cts-dev --module DevicePolicyManager --test com.android.cts.devicepolicy.CrossProfileAppsHostSideTest.testPrimaryUserToManagedProfile
Change-Id: I80d18f4e2ab76a228cb0aa2c8312c323a9b5c84d