feat(chat): Support extracting code blocks

[skarllot]

Pull Request

The issue or feature being addressed

• Code blocks are not supported

Details on the issue fix or feature implementation

• Create CodeExtractInstruction for supporting to extract code from code blocks

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

Attention: Patch coverage is 98.59155% with 1 line in your changes missing coverage. Please review.

Project coverage is 49.75%. Comparing base (bb3ee24) to head (238db24).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...t/Operations/ReviewChanges/ReviewChatDefinition.cs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #27      +/-   ##
==========================================
+ Coverage   46.75%   49.75%   +3.00%     
==========================================
  Files          62       64       +2     
  Lines        1172     1240      +68     
  Branches       94       99       +5     
==========================================
+ Hits          548      617      +69     
  Misses        612      612              
+ Partials       12       11       -1     

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