Support `@~latest` version when including components

What does this MR do and why?

This MR adds support to allow the version to be specified as ~latest when including components. The ~latest version is defined as: a special moving target version that points to the most recent released tag. The target project must be an explicit catalog resource.

Note that when the project does not have a release, it displays a "content not found" error (similar to when any target version does not exist).

Solves: Backend: Support `@~latest` version when includ... (#390839 - closed)

How to set up and validate locally

1. Enable the feature flag: Feature.enable(:ci_include_components)
2. Create a project with a component.

Path: /components/component-1/template.yml

template.yml:

component-1:
    script: echo

3. Mark the project as a catalog resource in the Rails console.

::Ci::Catalog::Resource.create(project: Project.find(<project_id>))

4. Create a new branch named branch-v0.1 with the following content in /components/component-1/template.yml:

component-1-v0.1:
    script: echo

5. Create a new branch named branch-v0.2 with the following content in /components/component-1/template.yml:

component-1-v0.2:
    script: echo

6. Go to Repository > Tags:

• Create a tag named v0.1 for branch branch-v0.1
• Create a tag named v0.2 for branch branch-v0.2

Screenshot

7. Go to Deployments > Releases. Create a new release for tag v0.1 for the current date.

Screenshot

8. Now go to CI/CD > Editor and update the content with the following YAML (adjusting the component path as needed):

include:
  - component: gdk.test:3000/group-a/project-components-1/components/component-1@~latest

9. Observe that there is no validation error.

And the "View merged YAML" content shows component-1-v0.1. Notice that it only retrieved the latest released tagged branch.

10. Commit the change and run the pipeline. It should succeed.

11. You can experiment with changing the release date to ensure that the @~latest keyword only retrieves the latest release tag. Also observe that if you remove all the releases or if the project is not a catalog resource, the following "content not found" error is displayed:

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #390839 (closed)