fix: allow url async calls to run in parallel

[cbaker6]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

Since async/await calls were introduced it made it a lot easier developers to make many async calls in parallel. Depending on how these async calls are made it's possible there can be a race condition in session delegates.

Also fixes a memory leak issue with Parse URL Session.

Related issue: #347

Approach

Use an actor for the url session delegates to ensure thread safety.

The updates make the test suite pass Xcode 14 beta 5 & 6.

TODOs before merging

• Add tests
• Add entry to changelog

[parse-github-assistant]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[cbaker6]

@vdkdamian can you try this branch out and let me know if you still see the issue you had?

[codecov]

Codecov Report

Merging #394 (e52969c) into main (e3e861d) will increase coverage by 0.43%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #394      +/-   ##
==========================================
+ Coverage   89.28%   89.72%   +0.43%     
==========================================
  Files         157      157              
  Lines       14970    15072     +102     
==========================================
+ Hits        13366    13523     +157     
+ Misses       1604     1549      -55     

Impacted Files	Coverage Δ
Sources/ParseSwift/API/API+Command.swift	89.38% <100.00%> (+0.17%)	⬆️
...urces/ParseSwift/API/ParseURLSessionDelegate.swift	100.00% <100.00%> (+84.21%)	⬆️
Sources/ParseSwift/Extensions/URLSession.swift	80.46% <100.00%> (+3.29%)	⬆️
Sources/ParseSwift/Parse.swift	91.35% <100.00%> (+0.07%)	⬆️
Sources/ParseSwift/Objects/ParseObject.swift	87.44% <0.00%> (+0.14%)	⬆️
Sources/ParseSwift/Objects/ParseUser.swift	86.34% <0.00%> (+0.16%)	⬆️
Sources/ParseSwift/LiveQuery/ParseLiveQuery.swift	76.75% <0.00%> (+0.58%)	⬆️

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[vdkdamian]

@vdkdamian can you try this branch out and let me know if you still see the issue you had?

Yes, give me some time. I'll try it as fast as possible