feat: update MFE to use dynamically injected theme

[ArturGaspar]

Description

Updates the MFE to use alpha version of frontend build, platform and paragon to support runtime theming.

Supporting information

https://openedx.atlassian.net/wiki/spaces/BPL/pages/3770744958/Migrating+MFEs+to+Paragon+design+tokens+and+CSS+variables

Testing instructions

1. Clone https://github.com/open-craft/edx-simple-theme and check out branch artur/design-tokens-update.
2. Build it (npm ci && npm run build).
3. Run a local server from the dist directory (e.g. python3 -m http.server 9100, use same port for brandOverride in MFE_CONFIG below).
4. Set MFE_CONFIG as in example Tutor plugin below.
5. Go to http://local.edly.io:8000/ and click Sign In
6. See that theming works.
7. Check that http://localhost:9100/light.min.css was loaded.

Example Tutor plugin to set MFE_CONFIG

name: mfe_config
version: 0.1.0
patches:
  mfe-lms-common-settings: |
    MFE_CONFIG.update({
        "PARAGON_THEME_URLS": {
            "core": {
                "urls": {
                    "default": "https://cdn.jsdelivr.net/npm/@openedx/paragon@$paragonVersion/dist/core.min.css",
                    "brandOverride": "https://cdn.jsdelivr.net/npm/@edx/brand-edx.org@$brandVersion/dist/core.min.css"
                }
            },
            "variants": {
                "light": {
                    "urls": {
                        "default": "https://cdn.jsdelivr.net/npm/@openedx/paragon@$paragonVersion/dist/light.min.css",
                        "brandOverride": "http://localhost:9100/light.min.css"
                    },
                    "default": True,
                    "dark": False
                }
            }
        }
    })

Deadline

None

Other information

Private-ref: https://tasks.opencraft.com/browse/BB-8118

[tecoholic]

@ArturGaspar 👍

• I tested this: Verified the that the file was loaded as expected.
• I read through the code
• I checked for accessibility issues
• Includes documentation