Ensure compatibility of frontend-app-learner-dashboard with @edx/brand theming style

[httpsmenahassan]

I tested frontend-app-learner-dashboard using the openedx brand theme and the style changes looked great. Nothing stuck out to me as a concern.

Here's the MFE with the openedx brand:

And here is it with edx.org brand. (default at the moment: #183)

Changes noticed when using openedx brand

• the header seems like it's doing the right things
  • the following items change from a more rounded appearance to a more straight lined appearance
    • the line below courses
    • the avatar button edges
    • view as: bar and submit buttons
  • there's also shading above and below the view as bars and submit button
• 'submit' button changes color from a purple-y to a muted red (overlay look)
• 'My Courses'/'Looking for a new challenge?'/'Explore our courses to add them to your dashboard.' - font weight and decreases and become a lighter black/dark gray
• 'Refine' button loses it's border and has overlay appearance
• 'Explore courses' button changes from rounded edges to sharp corners and the button color changes from a magenta purple to red
• 'Find a course' color change

[kdmccormick]

@brian-smith-tcril , looks like Mena did a spike here, and the result is that everything looks good? Gonna close, feel free to repoen if you think there are action items.