Limit organization switcher feature

Background

From #437541 (comment 1760906399)

It sounds like in Cells 1.0 switching organizations will not be supported. We need to modify the organization switcher to make this clear to the user

Proposal

In the organization switcher will display an empty state message that says Switching between organizations is not currently supported. Learn more.. The Learn more will link to the docs explaining roadmap. If you are a member of multiple organizations (in cells 1.0, this should only be possible for GitLab team members in the primary cell) those organizations will still show in Your work -> Organizations. You can still view them but you can't "switch" to them.

Implementation plan

• In app/assets/javascripts/super_sidebar/components/organization_switcher.vue#L63
  • Update so GraphQL request is always skipped
  • Removing loading state
  • I think we can use the footer slot to add this message, if not we may need to use a different strategy