Fix response/server streaming hang

[csvance]

After server ends the stream with END_STREAM streaming channels/tasks were not being closed.
Properly clean these up in cleanup_request which is called after curl signals CURLMSG_DONE

Fixes: #85

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.45%. Comparing base (1943d06) to head (a5f3c7b).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/Curl.jl	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #87      +/-   ##
==========================================
+ Coverage   83.39%   83.45%   +0.05%     
==========================================
  Files           7        7              
  Lines         554      556       +2     
==========================================
+ Hits          462      464       +2     
  Misses         92       92              

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