Let no-unsupported-configs rule check in next.config.ts

[lindelleric]

Let the eslint rule that checks the next config file also check for the typescript variants, which is now stable in next 15.

One could argue that only js|mjs|ts are needed since mts|cts|cjs are currently not supported yet. But it shouldn't hurt to allow them in the regex for when/if they are supported.

[changeset-bot]

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