WifiManager: Network request match callback registration

Add and Implement the new network request match callback register/unregister
@hide methods to be used by settings UI.

Note: This uses the same pattern used for other callbacks to settings
like traffic state change, softap.

Bug: 113878056
Test: ./frameworks/base/wifi/tests/runtests.sh
Change-Id: Ia4964759c6b10790dda0fc61a41c4d95dab904c9