Do not send socket destroyed on unregistration

When a SocketCallback is unregistered from MdnsSocketProvider, do not
send socket destroyed callbacks. Callers may not expect getting
callbacks after unregistration, and the current callbacks are also
broken when an unrequested socket is still in use by another requester.

MdnsAdvertiser already does not depend on getting this callback, as it
only unregisters the SocketCallback after it is done using the socket.
This change fixes MdnsMultinetworkSocketClient to destroy the socket by
itself when unrequesting.

Bug: 276177548
Test: atest
(cherry picked from https://android-review.googlesource.com/q/commit:5fe9bacc63c1b6a77878f23d5f53a07fc482f354)
Merged-In: If95f833e293f3aab91128aab1c9852ebfd41995d
Change-Id: If95f833e293f3aab91128aab1c9852ebfd41995d