Migrate /base to use @use (#10896)

[maureenlholland]

If this changeset needs to go into the FXC codebase, please add the WMO and FXC label.

One-line summary

Significant changes and points to review

Issue / Bugzilla link

Testing

[maureenlholland]

Don't configure in the includes file, only in the top level files

47.41 1 | throw new Error("Module build failed (from ./node_modules/sass-loader/dist/cjs.js):\nThis module was already loaded, so it can't be configured using \"with\".\n  ┌──> node_modules/@mozilla-protocol/core/protocol/css/includes/_lib.scss\n6 │ @forward 'config';\n  │ ^^^^^^^^^^^^^^^^^ new load\n  │ ━━━━━━━━━━━━━━━━━ original load\n  ╵\n  ┌──> media/css/base/banners/includes/_basic.scss\n5 │ @use '~@mozilla-protocol/core/protocol/css/includes/lib' as * with ($font-path: '/media/protocol/fonts', $image-path: '/media/protocol/img');\n  │ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ configuration\n  ╵\n  node_modules/@mozilla-protocol/core/protocol/css/includes/_lib.scss 6:1  @use\n  media/css/base/banners/includes/_basic.scss 5:1                          @import\n  media/css/mozorg/home/includes/monitor-banner.scss 9:9                   root stylesheet");

Issue (already configured by lib, doesn't want configuration on basic)

[maureenlholland]

test with !default vars too

[maureenlholland]

I don't think I can declare lib defaults from the base file: https://sass-lang.com/documentation/variables/#configuring-modules