Include SoftAP config in TetheringEventCallback

Include SoftApConfiguration in TetheringEventCallback via
TetheringInterface, to allow apps to know which interfaces are created
with their SoftApConfigurations.

API-Coverage-Bug: 371133403

Bug: 216524590
Test: atest TetheringTest CtsTetheringTest
Change-Id: I1b4868ba8327bee3b03c0f21e5b4f0845f2f24a8
9 files changed