Fix keyboard settings crash in multi-user case

We have CL[1] to fix the NPE when keyboard settings
is launched by work app. CL[1] overlooked the work
profile with multi-user case.

Work profile user ID is not available(return null)
when calling Utils#getManagedProfile by work identity.

For work case, distinguish it's running on managed
profile user(launched by work app) or not. And use
corresponding userId as:

-. If it's a managed profile user, use currentUserId.
-. For a owner user, get managed profile userId.

[1]: Iea573922ee789d9932c0de05bf71179c4f005eeb

Bug: 216395439
Test: Manual test with bugs steps
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AvailableVirtualKeyboardFragmentTest
Change-Id: If018d2fddbbcf932927d2235bb8e99393df1e67c