Make isDataEnabledForApn() a system api.

Test: atest TelephonyManagerTest#testIsDataEnabledForApn
Bug: 140763963
Merged-in: Icbb29124294972766f68533b7e23700dd491c075
Change-Id: Icbb29124294972766f68533b7e23700dd491c075
(cherry picked from commit 505e17417637dd02c12dd468b54e86f1c9c1ffe9)
2 files changed