Removing permissions for mItemsRestrictedOnHomeScreen UserProperty

Currently, `mItemsRestrictedOnHomeScreen` UserProperty can only be
accessed by system processes. This was causing
[failures](https://android-build.corp.google.com/test_investigate/?invocationId=I87900010248721608&testResultId=TR27929185691423632&tab=trace)
in postsubmit tests after flags were advanced to staging.

To fix this, the property above is changed to be unrestricted, to
allow Launcher process access.

Bug: 326158831
Test: atest UserManagerServiceUserPropertiesTest
Test: atest UserManagerServiceUserTypeTest
Test: atest FrameworksServicesTests:UserManagerTest
Change-Id: I35b71006a0ad10e062f8c543f73b3aac87322d0f