Revert "Enable manage mode for ExternalStorageProvider when called from Files"

This reverts commit c468e86a1be78f5141c03894e21abf6e99940108.

Reason for revert: Breaking DocumentsUIGoogleTests.
Bug: 150366834

Change-Id: I36cf4b43539008ae674918c7305e9de4d4449785
1 file changed