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Issue Description

When linting a project containing e.g. svelte files, you need to provide extraFileExtensions: ['.svelte'] to make the parser use the correct tsconfig for the specific file. This works well with project: true, since that path ends up in createWatchProgram where we provide the extraFileExtensions option to ts.

However, if we switch EXPERIMENTAL_useProjectService on, we end up in a code path where the extraFileExtensions are not passed to ts. In my reproduction case this is surfaced by the fact that ts will then use the default compiler options, which transpiles the code back to ES5, instead of using the correct tsconfig.

While this reproduction example is using Svelte, the same issue should apply to other cases where extraFileExtensions would be used (such as when using Vite).

Reproduction Repository Link

https://github.com/alfredringstad/typescript-eslint-svelte-use-project-service-bug-reproduction

Repro Steps

1. clone the repo
2. npm i
3. npm run lint

Switch EXPERIMENTAL_useProjectService to false in eslint.config.js and run npm run lint to see how it works well without the project service.

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