fix: Annotations tooltip logic

What does this MR do?

Background: Currently, annotations in the monitoring dashboard are generated by passing series via the option instead of the annotation prop. This is because the deployments are still in GitLab and not in GitLab UI. It is ideal to have both the annotations and deployments in one place. So until deployments are deprecated, moving the annotation logic from GitLab to GitLab UI is not an ideal move.

When Annotation markers were added to GitLab UI !1337 (merged), I was hoping to move annotations to GitLab UI but, as mentioned above, it wasn't the best choice. This resulted in breaking the annotations.

This MR makes sure that annotations logic is backwards compatible i.e. for cases where annotations are passed via option props.

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines.
• GitLab UI's contributing guidlines.
• If it changes a Pajamas-compliant component's look & feel, the MR has been reviewed by a UX designer.
• If it changes GitLab UI's documentation guidelines, the MR has been reviewed by a Technical Writer.
• If the MR changes a component's API, integration MR(s) have been opened in the following projects to ensure that the @gitlab/ui package can be upgraded quickly after the changes are released:
  • GitLab: mr_url
  • Customers Portal: mr_url
  • Status Page: mr_url
• Added the ~"component:*" label(s) if applicable.