Moarrr changes on 'cmd user set-system-user-mode-emulation'

- Updates system user packages.
- Fails when system user has a credential.

Test: adb shell cmd user set-system-user-mode-emulation full # on HSUM device
Test: adb shell dumpsys user | grep -A 2 headless
Bug: 226643927

Change-Id: Ia9426912157547e09ed2232a2f5a9d2af2b10aea