[HSUM] Modify UserManagerStateTest to use current user instead of SYSTEM

user

Test: atest UserManagerStateTest

BUG: 383496661
BUG: 383496146
BUG: 383282050
BUG: 383281833
BUG: 383281571
BUG: 383281361
BUG: 383281338
BUG: 383180103

Flag: EXEMPT test fix only
Change-Id: I16dffd4ba1a6ab7febca67bd3ace9fc5ac891073