Fixed websocket support in hs.httpserver:start()

[latenitefilms]

• Closes Why is an HTTP callback required if I only want a WebSocket server in hs.httpserver? #3468

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 27.70%. Comparing base (ec9a8ea) to head (45eaf01).
Report is 16 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3665      +/-   ##
==========================================
+ Coverage   27.65%   27.70%   +0.04%     
==========================================
  Files         191      191              
  Lines       43472    43528      +56     
==========================================
+ Hits        12023    12059      +36     
- Misses      31449    31469      +20