Merge "Added javadoc to apn retry \ throttling related methods" am: 6fccdbb8d3

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1598494

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I1d0a35d009f3d66dd1800ea44f6d429c9f9e0c94