Move component stylesheets to load dynamically with render

[aduth]

🛠 Summary of changes

This builds upon #8375, shifting many of the existing stylesheets to be implemented as component-specific stylesheets. The benefits of this are outlined in #8375.

In practice, this means the application stylesheet is slightly smaller, instead loading many individual component stylesheets. There's a bit of a tradeoff here since the application stylesheet reduction is mitigated slightly by Brotli/DEFLATE's internal characteristics to reconcile duplication, which is not as effective in smaller, individual stylesheets. This would be most noticeable for components implemented in common layout or critical paths, e.g. language picker or Sign In page elements. Overall, I personally think it's still a net positive, all things considered.

This was originally going to include a refactor of LanguagePickerComponent to have a component stylesheet, but there's an issue with how we render the "stylesheet once" tags which is incompatible with components rendered as part of the base layout. This will need to be fixed first.

Performance Results

NODE_ENV=production yarn build:css && brotli-size app/assets/builds/application.css

Before: 26.9kb
After: 26.4kb
Diff: -0.5kb (-2%)

📜 Testing Plan

Ensure no regressions in the appearance of the affected components.

[aduth]

There's a small issue with the per-component stylesheets that I need to fix before merging this. Stylesheets which customize the font (example) are not outputting those styles when separated from the main application stylesheet, due to the optimization to avoid rendering font declarations in all except the main application stylesheet. It seems that USWDS detects that those fonts aren't configured and refuses to output the font style.

For example, in this branch, the OTP code entry field shows with normal text, but it's meant to show with monospace text.

[aduth]

There's a small issue with the per-component stylesheets that I need to fix before merging this. Stylesheets which customize the font (example) are not outputting those styles when separated from the main application stylesheet, due to the optimization to avoid rendering font declarations in all except the main application stylesheet. It seems that USWDS detects that those fonts aren't configured and refuses to output the font style.

For example, in this branch, the OTP code entry field shows with normal text, but it's meant to show with monospace text.

I think I found a resolution for this in 99a2196, which is a bit simpler overall as well.