Fix ClipboardService's auto-clearing where wrong uid was being used.

- Autoclear option was not clearing the clipboard because auto-clear path was using Binder.getCallingUid() instead of the uid to resolve the userId which the primary clip is set against.

Fix: 232809658
Test: atest ClipboardAutoClearTest
Change-Id: Iae4f1a1d7cbc85212916658cd779e806ebdf2270