Block settings when DISALLOW_CONFIG_DATE_TIME.

Test: m -j RunSettingsRoboTests
runtest -x packages/apps/Settings/tests/unit/src/com/android/settings/core/UserRestrictionTest.java

Fix: 67497909

After turn on the user restriction in TestDPC:
https://hsv.googleplex.com/5414119658225664
The date time settings page become:
https://hsv.googleplex.com/5199302573948928


Change-Id: I42590c4a505ec1b6ffa86eb460b90fa6ec8ba783