fix: resolve side effect imports

[felix-roehrich]

@sveltejs/package does not resolve aliases for side effect imports. This is annoying when you have global CSS in your library and want to import that in Svelte components. With this PR side effect imports are now also resolved.

I have added tests for this, but the behaviour for the .d.ts file is weird. When using the currently published version, the CSS import is stripped from .d.ts file, but for the tests it is still there.

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🦋 Changeset detected

Latest commit: b8a6c76

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/package	Patch

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