Improve people access invite flow

[markverick]

Summary

Improve the workspace people/access UI so the invite flow is clearer and users can copy the invite link after creating invitations.

Changes

• Rename sidebar entry from Invite people to People & access
• Use a users icon instead of a plus icon
• Keep the invite modal open after invitations are created
• Rename modal action from Invite to Create invitations
• Show a success message telling users to share the invite link
• Change Cancel to Close when there are no pending invitees
• Show Revoke access is not implemented yet on the disabled member action tooltip

Testing

• Verified only UI files were committed
• Ran type-check locally