Generate request config typescript fetch v2

[azertyalex]

Original pr that broke master branch: #21709

This PR splits some logic, instead of creating/building the request inline and sending it instantly we now use a function to do this. Functionally there should be no changes.

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  ./mvnw clean package || exit
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---

Summary by cubic

Introduces per-operation request option builders in the TypeScript Fetch generator, separating request construction from sending. Adds flexibility for pre-inspecting or customizing requests with no runtime behavior change.

• Refactors
  • Adds RequestOpts methods to generated interfaces and classes, returning runtime.RequestOpts.
  • Raw methods now call request() with options from RequestOpts; public APIs remain the same.
  • Removes initOverrides from RequestOpts signatures; pass initOverrides only to raw/request calls.
  • Updates all TypeScript Fetch samples and docs to use the new RequestOpts pattern.

^{Written for commit bb42080. Summary will update on new commits.}

[azertyalex]

My last pr broke main (#21709). I made the necessary changes starting from my original commit.
Very sorry for the inconvenience. I hope my contribution will still be looked at if you'll have me

[azertyalex]

@TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02) @davidgamero (2022/03) @mkusaka (2022/04) @joscha (2024/10)

[cubic-dev-ai]

No issues found across 50 files

[azertyalex]

fixes: #21708

[wing328]

let's give it a try

we can further update it with separate PRs if needed