Overloading A11yManager#getEnabledA11yServiceList to optionally accept userId

Allows the above function to take userid, for situations in which userId needs to be correct during user switching

Test: atest AccessibilityShortcutControllerTest
Bug: 396522300
Flag: EXEMPT refactoring
Change-Id: I62efda0479181b6717d2b8061eaa3d4fe9769afd