Close the links after closing the Face

[Hugal31]

This is another attempt to minimize the occurrence of the race condition described in #1886.

When loosing the connection to a peer, if the send buffer happens to fill up before the keep alive timeout, the tx_task can be stuck in the send_batch operation. On my computer, it can be stuck for 15 minutes before returning with EHOSTUNREACH ("No route to host").

Now this is not that bat itself, it's just a dangling task, a TransportLinkUnicastUniversal and a TransportUnicastUniversal. But this make the race condition mentioned in #1886 very likely: if the peer reconnect within those 15 minutes, the re-connection is bogus.

This "fix" make TransportUnicastUniversal::delete() notify the RuntimeSession of the transport deletion before closing the link, instead of after closing the link. It doesn't seem to cause any issue. I didn't do the same in TransportUnicastLowlatency because I am not sure it is necessary.

I am not really happy with this hack, because I don't fully understand the consequences of the fix and it just make the race-condition a lot less likely (15min time span vs a few milliseconds). Have a look at #1886 for more information.

[github-actions[bot]]

PR missing one of the required labels: {'dependencies', 'breaking-change', 'enhancement', 'internal', 'bug', 'new feature', 'documentation'}

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 70.89%. Comparing base (b33ddc3) to head (a120311). :warning: Report is 53 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1979      +/-   ##
==========================================
- Coverage   71.03%   70.89%   -0.15%     
==========================================
  Files         364      364              
  Lines       61519    61519              
==========================================
- Hits        43699    43612      -87     
- Misses      17820    17907      +87     

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