Cleanup the public API getActiveNetworkForUid on AOSP

Use reflection method to replace the use of public api
getActiveNetworkForUid.

Android 12 version, the public API getActiveNetworkForUid and all
(outside the module) callers of the API have been removed and replaced.

Unfortunately, the related delete/replace code cannot be synced to AOSP
,so in order to keep the public api consistent in Android 12 & AOSP,
The commit uses reflection method to replace the caller of this public
api, Then we can delete this public API in another commit in AOSP.

Bug: 183465229
Test: atest ConnectivityControllerTest
      atest CtsJobSchedulerTestCases:ConnectivityConstraintTest
Merged-In: Ie93cd22b11cc28135a385c0cf6ad6b577b61d1b7
Change-Id: Ia636480b12a9b4a9e2c5dd2ec9259af3167df909