Combine Google Fonts into a single preconnected request

[julioalucero]

FR-744: Redundant Google Fonts requests

Link to Jira

FR-744: Redundant Google Fonts requests

PR description

The styleguide fired two separate render-blocking Google Fonts requests via @import inside the shared SCSS. That runs on every consumer, can't be deduped, and can't be preconnected.

• Removed both @import url() from vendor/.../2-quarks/_typography.scss; font loading now belongs to the consuming app.
• Removed the same two @imports from the compiled static/styleguide.css and .min.css.
• Added preconnect hints + one combined <link> (both families in a single request) to index.html for the demo page.

PR related: https://github.com/ombulabs/fastruby.io/pull/1153

QA steps

1. Open index.html, DevTools => Network, filter css, should be one css2 request, not two.
2. Check Oxygen and Source Code Pro still render correctly.
3. Confirm it on Fastruby.io, which looks the same, and make one request.

Notes

• Similar Request at: OMBU-793: Combine Google Fonts into a single non-blocking request ombulabs/styleguide#69