Refactor some codes for unbundle

1. Move some @hide codes to DocumentsUI itself utils files.
2. Refactor some @hide api call to normal api call
   for same function
3. Remove unnecessary @hide api call.

Bug: 118794189
Bug: 118271458
Test: atest DocumentsUITests
Change-Id: I319ee2149d7594e20287638037739cc5ee4b0554