Add Storybook tests and accessibility checks to CI

What does this MR do and why?

Run Storybook tests and accessibility checks in CI

Set as allowed to failed. Will be changed later on, once we address the found issues.

The goal is to have an automated feedback on Vue components' accessibility.

References

• discussion on the specifics of the CI job: #507448 (comment 2653405943)

Screenshots or screen recordings

Screenshot of the shared component corrected to trigger frontend pipeline:

Before	After

How to set up and validate locally

MR acceptance checklist

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Related to #507448 (closed)