fix: update Solid Start default port

[nickytonline]

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Summary

The default port for Solid Start has been updated to 5173, the new default port for vite

Fixes #4844

This was required because running ntl dev with no netlify.toml caused Solid Start's dev server running in the Netlify CLI to hang because it was waiting on port 3000 previously.

The steps to replicate the issue are in #4844 as well as setting it to 5173, showing it working.

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