Adds organization context for the registrations features specs

What does this MR do and why?

As organization is going to be mandatory on the namespace/project level, we're including them on the registrations feature specs.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

N/A

How to set up and validate locally

1. Checkout the bmarjanovic/update-registrations-feature-specs branch
2. Add the organization validation to the project class

   validates :organization, presence: true

3. Run the changed specs to verify that everything works as expected 🎉