Disposing pipeline should not dispose external inner pipeline

[martintmk]

Details on the issue fix or feature implementation

If resilience pipeline uses other pipeline it should not own it. Therefore the pipeline is disposed, the "external' pipeline should still stay alive as it's lifetime is managed outside of current pipeline.

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.01% 🎉

Comparison is base (5baee94) 83.98% compared to head (d63d5c6) 83.99%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1529      +/-   ##
==========================================
+ Coverage   83.98%   83.99%   +0.01%     
==========================================
  Files         278      279       +1     
  Lines        6542     6547       +5     
  Branches     1023     1023              
==========================================
+ Hits         5494     5499       +5     
  Misses        839      839              
  Partials      209      209              

Flag	Coverage Δ
linux	?
macos	83.99% <100.00%> (+0.01%)	⬆️
windows	83.99% <100.00%> (+0.01%)	⬆️

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Files Changed	Coverage Δ
src/Polly.Core/ResiliencePipelineBuilderBase.cs	100.00% <ø> (ø)
src/Polly.Core/Utils/Pipeline/ExternalComponent.cs	100.00% <100.00%> (ø)
...ly.Core/Utils/Pipeline/PipelineComponentFactory.cs	100.00% <100.00%> (ø)
src/Polly.Testing/ResiliencePipelineExtensions.cs	100.00% <100.00%> (ø)

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