Create new DataEnabledReasons for for DataSettingsManager

DataEnabledSettings used an internal DataEnabledChangedReason when
notifying data enabled was changed. For DataSettingsManager, sync the
reasons with TelephonyManager#DataEnabledReasons and remove the internal
reaons.

Test: atest FrameworksTelephonyTests
Bug: 204309297
Change-Id: I8d6fd13e319ce165e25f2afd93bf9884fbf22667