feat(S2): show a console warning when content components are used standalone

[reidbarber]

When content components (Text, Heading, etc.) are used standalone, they don't inherit any styles. This PR's change will show a warning in this case, so the user knows to use native HTML elements with the style macro instead.

This change is also oriented to AI tools that frequently make this mistake, although it seems like they more often look at lint errors instead of browser errors. Not sure this is something we can catch with a lint plugin.

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

See unit tests.

🧢 Your Project:

[reidbarber]

I guess we probably added this for Skeleton loading capabilities. I can see if we go back to Text and update our hook to detect this instead.

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs

[snowystinger]

don't need textValue either then?

[snowystinger]

this is just checking props, would it be better to check that there's a context object? otherwise you wont' get the warning sometimes

you could pass the context to retrieve instead of props
useWarnIfNoStyles('Heading', HeadingContext);

then in the hook, useContext(Context) and just check if that returns an object at all