clear calling identity before calling settings provider

Test: Run a instrumentation test
cts-tradefed run cts-dev --module DevicePolicyManager --test com.android.cts.devicepolicy.ManagedProfileTest#testPhoneAccountVisibility

Change-Id: I29b1dc307e9e127b919aebe4d83ab6311ce36f2d
Fix: 34320197
1 file changed