Do not close client after loader loading finished

MediaProvider send contents change notification to background process
with delay so DocsUI should not close provider client after loading
finished, and it will close automatically after application finished.

Fix: 141473235
Test: manual
Test: atest DocumentsUIGoogleTests
Change-Id: Icc2ad660a9ad8f215ef1cd6edba7a5f3498f7287
3 files changed