Added IAsyncDisposable to TestServiceProvider

[egil]

Pull request description

PR meta checklist

• Pull request is targeting at DEV branch.
• Pull request is linked to all related issues, if any.
• I have read the CONTRIBUTING.md document.

Content checklist

• My code follows the code style of this project and AspNetCore coding guidelines.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• I have updated the appropriate sub section in the CHANGELOG.md.
• I have added, updated or removed tests to according to my changes.
  • All tests passed.

[codecov]

Codecov Report

Merging #292 (6f72e88) into dev (51d6b81) will increase coverage by 0.01%.
The diff coverage is 60.00%.

@@            Coverage Diff             @@
##              dev     #292      +/-   ##
==========================================
+ Coverage   82.69%   82.71%   +0.01%     
==========================================
  Files         126      126              
  Lines        3710     3714       +4     
  Branches      481      482       +1     
==========================================
+ Hits         3068     3072       +4     
  Misses        493      493              
  Partials      149      149              

Impacted Files	Coverage Δ
src/bunit.core/TestServiceProvider.cs	93.22% <60.00%> (-3.15%)	⬇️
...it.core/Extensions/WaitForHelpers/WaitForHelper.cs	90.47% <0.00%> (+2.38%)	⬆️

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