fix: detect next if typescript config file is used

[pieh]

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Summary

next@15 added support for next.config.ts: https://nextjs.org/blog/next-15#support-for-nextconfigts

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Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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