Fix ClipboardService device lock check for cross profile

ClipboardService.isDeviceLocked should clear callingIdentity before
accessing KeyguardManager.

Test: bit CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.ManagedProfileTest

Bug: 64934810
Change-Id: I712abfe8d542cd1be9c1816f407c8912321ac480
1 file changed