Fixed VIMS to postpone ASSISTANT rule change on pre-created users.

RoleService should not be calling onRoleHoldersChanged() on
pre-created users, but that behavior cannot be changed because its
implemented by a system app, and pre-created users APIs are hidden.

To test it:

$ adb shell pm create-user --pre-create-only  --guest
Success: created user id 12

$ adb shell pm create-user --guest ElGuesto
Success: created user id 12

$ adb shell cmd user list --all -v
4 users:

0: id=0, name=Driver, type=system.HEADLESS, flags=ADMIN|INITIALIZED|PRIMARY|SYSTEM (running)
1: id=10, name=Driver, type=full.SECONDARY, flags=ADMIN|FULL|INITIALIZED (running) (current)
2: id=11, name=null, type=full.SECONDARY, flags=FULL|INITIALIZED (pre-created)
3: id=12, name=ElGuesto, type=full.GUEST, flags=EPHEMERAL|FULL|GUEST|INITIALIZED (converted)

$ adb shell am switch-user 12

$ adb shell dumpsys voiceinteraction |egrep '(mBound|implementation)'
  mBound=true mService=android.service.voice.IVoiceInteractionService$Stub$Proxy@77da1bc

$ adb shell cmd voiceinteraction show

Test: see bove
Bug: 216141085
Bug: 226201975

Change-Id: I12d9bb32e144ecf91ee4b452affea0dcea546127