Align SiteHeader

[emilyjablonski]

Even though there’s a fair amount of changes to the SCSS file, they’re mostly around variables and I actually think it’s worth it in this case to see what the new variables are and pull them back to UIC where helpful.

Even though this component won’t exist in Seeds, when we move it to where it should live in core, it’s still helpful to have those variable overrides in a local component for forked consumers to customize if they have light changes without having to make a change to the SCSS file itself to stay in sync.

[sarahlazarich]

There are some variables changes, Emily already solved a lot of thus on link wrapping issue
Ideal case after this, DW will pull in UIC siteheader, but might need to pull more variables in to make that happen
Design confirmed!