refactor(api-markdown-documenter): Make configuration properties readonly

[Josmithr]

Makes a number of configuration properties readonly.

Copilot reviewed 5 out of 12 changed files in this pull request and generated no comments.

Files not reviewed (7)

• tools/api-markdown-documenter/src/documentation-domain-to-html/configuration/Transformation.ts: Evaluated as low risk
• tools/api-markdown-documenter/src/renderers/html-renderer/Render.ts: Evaluated as low risk
• tools/api-markdown-documenter/src/renderers/markdown-renderer/RenderContext.ts: Evaluated as low risk
• tools/api-markdown-documenter/src/renderers/markdown-renderer/configuration/RenderOptions.ts: Evaluated as low risk
• tools/api-markdown-documenter/src/api-item-transforms/configuration/TransformationOptions.ts: Evaluated as low risk
• tools/api-markdown-documenter/src/api-item-transforms/configuration/Configuration.ts: Evaluated as low risk
• tools/api-markdown-documenter/src/api-item-transforms/configuration/DocumentationSuiteOptions.ts: Evaluated as low risk

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> fluid-framework-docs-site@0.0.0 ci:check-links /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test "npm run serve -- --no-open" 3000 check-links

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-docs-site@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-docs-site@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  170138 links
    1596 destination URLs
    1825 URLs ignored
       0 warnings
       0 errors