User: Main CTA in the invitation signup screen has wrong color

[mmtr]

Issue reported during walkthrough: p58i-iKo-p2

When a user receives an invitation to join a site and click on the link, they see this screen whose main button has the old blue. It should be updated to the new WordPress blue.

[github-actions[bot]]

OpenAI suggested the following labels for this issue:

• [Feature Group] Signup & Site Onboarding: The issue relates to the signup process where users receive an invitation to join a site.
• [Feature] Customizer: The problem involves the appearance of a call-to-action button, which can be customized through the Customizer.
• [Feature] Global Styles: The issue pertains to the styling of the main button, which should adhere to the global styles of WordPress.
• [Feature] Signup & Account Creation: This directly relates to the creation of a new account following an invitation, which is part of the user onboarding experience.