fix(dev): fix JSX in JS files with CSS imports

[markdalgleish]

Closes: #5331

This fixes an issue where the CSS side-effect imports plugin mistakenly assumed that JS files don't contain JSX, but this is out of step with the rest of Remix.

I've validated that .mjs and .cjs files don't support JSX in Remix, so this issue only affects JS files.

I've added a test to catch this, ensuring that the test fails against the latest code in dev.

[changeset-bot]

🦋 Changeset detected

Latest commit: 16d525e

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

This PR includes changesets to release 18 packages

Name	Type
@remix-run/dev	Patch
create-remix	Patch
@remix-run/css-bundle	Patch
remix	Patch
@remix-run/architect	Patch
@remix-run/cloudflare	Patch
@remix-run/cloudflare-pages	Patch
@remix-run/cloudflare-workers	Patch
@remix-run/deno	Patch
@remix-run/eslint-config	Patch
@remix-run/express	Patch
@remix-run/netlify	Patch
@remix-run/node	Patch
@remix-run/react	Patch
@remix-run/serve	Patch
@remix-run/server-runtime	Patch
@remix-run/testing	Patch
@remix-run/vercel	Patch

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[github-actions]

🤖 Hello there,

We just published version v0.0.0-nightly-6e23fcf-20230505 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 1.16.1-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 1.16.1 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!