Revoke all relevant shared permission on uninstall

The for-loop over the uninstalled app's permissions would
previously return immediately after successfully revoking
a shared permission, preventing the loop to run to the end.

Instead, always loop through all the permission and return
the "widest" matching user id.

Bug: 36899497
Test: manual, using provided test apks
Test: atest CtsPermissionTestCases:SharedUidPermissionsTest
Change-Id: I1f8fad77123c8affa2d825bce1edc2bcd8f60f12