HintManagerService: allow application to create session for non-calling-processes.

Currently isolated processed cannot use HintManagerService due to
sepolicy. This change is to allow application to create sessions for its
other isolated/non-isolated processes.

Bug: 191703385
Test: atest HintManagerServiceTest
Signed-off-by: Wei Wang <wvw@google.com>
Change-Id: If784a7f620edcf8d5ca9b7fb8dfa2358269f1eac