Indicate that no additional integrations can be added for Core users
Release notes
Problem to solve
The ability to add multiple integrations will be a premium feature. Core users can only add one integration of each type. How do we indicate to Core users that only one integration of each type can be added?
Intended users
User experience goal
Communicate to Core users that only one integration / type can be added
Proposal
For users on a Core subscription plan: if they have an HTTP Endpoint or a Prometheus integration already set up, the option is disabled in the integration type dropdown.
Additionally, we'll add the following text to the intro for Core users only:
In free versions of GitLab, only one integration for each type can be added. [Upgrade your subscription](url) to add additional integrations.
This sentence will either be added underneath the "Add new integrations" heading or at the end of the intro copy, depending on where we're at with the custom alert integrations work. It would be great to link the update subscription text to the appropriate page. Perhaps --> https://about.gitlab.com/pricing/ is most appropriate?