Bump axios and @openapitools/openapi-generator-cli in /examples/nextjs (#573)

Bumps [axios](https://github.com/axios/axios) and [@openapitools/openapi-generator-cli](https://github.com/OpenAPITools/openapi-generator-cli). These dependencies needed to be updated together.

Updates `axios` from 1.13.2 to 1.13.5
- [Release notes](https://github.com/axios/axios/releases)
- [Changelog](https://github.com/axios/axios/blob/v1.x/CHANGELOG.md)
- [Commits](axios/axios@v1.13.2...v1.13.5)

Updates `@openapitools/openapi-generator-cli` from 2.25.2 to 2.28.3
- [Release notes](https://github.com/OpenAPITools/openapi-generator-cli/releases)
- [Commits](OpenAPITools/openapi-generator-cli@v2.25.2...v2.28.3)

---
updated-dependencies:
- dependency-name: axios
  dependency-version: 1.13.5
  dependency-type: indirect
- dependency-name: "@openapitools/openapi-generator-cli"
  dependency-version: 2.28.3
  dependency-type: indirect
...

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Author: dependabot[bot]