feat(ssr): warn if cant analyze dynamic import

[bluwy]

Description

If SSR contains a dynamic import that can't be analyzed, warn about it. (similar to client)

Also only warn if the file we're analyzing is not in node_modules, since the user likely can't do anything except patching. (Could hide potential problems but maybe the cases are rare 🤔 )

Ref withastro/astro#3373 (comment)

Additional context

Happy to discuss each changes, maybe I'm missing some important aspects.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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