UserTypeDetails.dump restrictions for SYSTEM

The SYSTEM user does not get its default restrictions
from UserTypeDetails.mDefaultRestrictions; rather it gets
it from config_defaultFirstUserRestrictions. Therefore, we
now dump those restrictions from the latter (instead of
the former) for the SYSTEM user.

Fixes: 146793707
Test: manual check of: adb shell dumpsys user
Change-Id: I5cf04d20fe9edd748803634ec80336b267695ce6
Merged-In: I5cf04d20fe9edd748803634ec80336b267695ce6