Sub-issue description

As we onboard more users to Enterprise mode (EM), we will eventually onboard some organizations where people manage domains that are in an org, and domains that are not yet on EM. We want to make sure that the experience for this is easy to use and navigate, and doesn't remove expected functionality. This issue is to implement the designs to switch between the experiences.

Depending on the scope of changes, this can be split into multiple tickets to account for dependencies and/or atomic areas of work

Reviewing the tickets in M7 #3651 might be helpful
For any design questions or a design review (if needed), reach out to @gabo0oo

Acceptance criteria

(These are included in sub-issues with more detail where applicable)

Org switcher page

• Annotation 1 Add new 'Enterprise' tag to newly created organization switcher page.
• Annotation 2 Update microcopy

Navigation update (Organization dropdown)

• Annotation 3 Add new tags to differentiate portfolio orgs from personal account on Organization dropdown

Navigation update (Login and Home button logic)

• Add logic for routes to the "Your Organizations" page so that it shows when a user has legacy domains AND one or more portfolios (currently, only users with multiple portfolios can see the "Your Organizations" page. We want to augment this so that users with legacy domains AND one or more portfolios are also routed to that page on login and when the Home button is pressed)

Styling updates to legacy UI

• Annotation 4 Update header styling to unify legacy and EM experiences
• Annotation 5 Change background color of dashboard page

Additional context

Slack