Provide SCTP Association OnClose callback

[sukunrt]

Porting #2858 to v3.

[codecov]

Codecov Report

Attention: Patch coverage is 68.75000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 80.19%. Comparing base (4e4a67d) to head (484d89a).

Files	Patch %	Lines
sctptransport.go	68.75%	4 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##               v3    #2861      +/-   ##
==========================================
- Coverage   80.19%   80.19%   -0.01%     
==========================================
  Files          78       78              
  Lines        7599     7614      +15     
==========================================
+ Hits         6094     6106      +12     
- Misses       1070     1072       +2     
- Partials      435      436       +1     

Flag	Coverage Δ
go	80.19% <68.75%> (-0.01%)	⬇️

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