Make the Hero Card SDC Canvas-eligible on Drupal 11.4 (valid button_1_url example)

Problem/Motivation

On Drupal 11.4, Drupal Canvas validates every SDC prop's examples value against its declared format. The Hero Card SDC (components/organisms/card-hero/card-hero.component.yml) declares a button_1_url prop with format: uri-reference, but its examples value is "#", which fails uri-reference validation ("Invalid URL format"). Canvas therefore marks the whole Hero Card component INELIGIBLE, so it disappears from the Canvas component library. This breaks the varbase_project functional test 09-04-canvas-hero-cards.feature ("Hero Card component did not appear in the Canvas Library").

This exact one-line fix was already made in commit 01e784c2 on the vartheme_bs5 issue fork branch 3607734-update-drupal-core (issue #3607734), but that commit landed after the #3607734 MR had already merged, so it never reached canonical 5.0.x and has no MR of its own. Filing this fresh issue to land the fix on canonical 5.0.x (referencing #3607734 for context only; that issue is Closed/Fixed).

Steps to reproduce

1. Install a site with Vartheme BS5 5.0.x on Drupal 11.4 with Drupal Canvas enabled.
2. Open the Drupal Canvas component library.
3. Observe that the Hero Card component is missing/ineligible from the library.
4. Inspect components/organisms/card-hero/card-hero.component.yml: the button_1_url prop has format: uri-reference and examples: - "#", which fails uri-reference validation.

Proposed resolution

Change the button_1_url prop's examples value in components/organisms/card-hero/card-hero.component.yml from "#" to a valid absolute URL, e.g. "https://example.com", so it passes uri-reference validation and the Hero Card component becomes Canvas-eligible again. The default: "#" value is left unchanged.

Remaining tasks

• ✅ 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
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ❌ Update Release Notes
• ❌ Release

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• N/A