Revert "Write policy file on background thread"

Bug: 120445316
Test: atest NotificationManagerServiceTest

This reverts commit a5287dc1cd6ea03e58f5e5ad8912bfbe2d35faf2.

Reason for revert: Breaking test

Change-Id: I8cb5ebdfbb727ab9bebf945f9ab85b0227913027
1 file changed