Issue #3592934: Add Hero Slider Canvas functional coverage

Functional coverage for the Bootstrap 5 carousel-based Hero Slider (sdc.vartheme_bs5.hero-slider-container) supporting Drupal Canvas.

Scenarios (7, all passing on a fresh Varbase install)

• Homepage hero slider renders a working carousel: indicators, prev/next controls, autoplay (data-bs-ride / data-bs-interval).
• Hero slides show different styles: multiple slides, the active slide, overlay content and a button.
• Styling in the editor (Scenario Outline): a site builder drags the Hero Slider (Container) from the Library onto a new page, sets a style option in the Settings panel, publishes, and the rendered carousel is verified - across a matrix of styles: fade transition, slider height 500/900, controller colour dark/light.

Reuses the Drupal Canvas editor steps (drag a component onto the canvas, set a component option, publish) introduced with the Hero Card coverage. Design reference: VB Approved Stylesheet (Figma).

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AI-Generated: Yes (Used Claude Code to draft the Gherkin scenarios. All scenarios were executed and pass against a fresh Varbase install; the contributor reviewed the changes and remains responsible for their integrity.)

Checkpoints

• File an issue about this project
• Addition/Change/Update/Fix to this project
• Testing to ensure no regression
• Automated unit/functional testing coverage
• Developer Documentation support on feature change/addition
• User Guide Documentation support on feature change/addition
• UX/UI designer responsibilities
• Accessibility and Readability
• Code review from 1 Varbase core team member
• Full testing and approval
• Credit contributors
• Review with the product owner
• Update Release Notes
• Release