Gutenboarding: Show “Pick a domain” when user haven’t entered site title and haven’t decided on a domain. #3646539

Changes proposed in this Pull Request

• Show “Pick a domain” when user haven’t entered site title and haven’t decided on a domain.

Testing instructions

• Go to /new
• Click “Skip for now”.
• Domain picker button’s label should be “Pick a domain”.
• Open up domain picker, select a domain and click Confirm.
• Domain picker button’s label should be the selected domain name.

Screenshot

Fixes #42524