typescript-axios: support TypeScript 6

[Felix-ming]

Summary

• Include TypeScript 6 in the generated typescript-axios development dependency range.
• Add a regression test for the generated package.json.

Closes #24830.

Validation

• git diff --check passed.
• Regenerated both CI-targeted TypeScript Axios samples locally with JDK 21 using ./bin/generate-samples.sh ./bin/configs/typescript-axios-echo-api.yaml ./bin/configs/typescript-axios-es6-target.yaml; both generators succeeded.
• The targeted Maven regression test passed locally: ./mvnw -pl modules/openapi-generator -am -Dtest=TypeScriptAxiosClientCodegenTest -Dsurefire.failIfNoSpecifiedTests=false test (15 tests, 0 failures). The latest PR workflow runs are awaiting maintainer approval.
• The issue reporter confirms their generated client compiles with TypeScript 6.

Prepared with AI assistance.

---

Summary by cubic

Makes the typescript-axios generated clients work with TypeScript 6. Closes #24830.

• Expands the generated devDependency range to ^4.0 || ^5.0 || ^6.0.
• Removes the deprecated moduleResolution: node setting from generated ES6 tsconfig files so TypeScript 6 can use its compiler default.
• Adds a regression test asserting the new dependency range and the omitted tsconfig setting, and regenerates the affected samples.

^{Written for commit 5aa3707. Summary will update on new commits.}

[cubic-dev-ai]

All reported issues were addressed across 2 files

<sub>Reply to a comment to ask cubic a question or push back. It learns from your replies.

Re-trigger cubic</sub>

[wing328]

thanks for the PR

cc @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) @KannaKim (2026/07)

[wing328]

please update the samples to fix https://github.com/OpenAPITools/openapi-generator/actions/runs/37507777157/job/112613481427?pr=25148

[Felix-ming]

Updated the three generated TypeScript Axios samples flagged by the Samples up-to-date check (with-complex-headers, with-npm-version-and-separate-models-and-api, and with-npm-version) to include ^6.0 in their TypeScript devDependency ranges. The changes match the expected generated output. Thanks!