Update alias package @edx/brand to @openedx/brand

[feanil]

We currently have a package named @edx/brand that we use as a part of frontend theming. This package does not exist and is always expected to be aliased to a different package based on your theme. The default being @openedx/brand-openedx.

AC:

• All openedx packages should be using @openedx/brand as the default name for this package.
• All imports should be updated so that they continue to work with the new name.