Update Drupal Core to ~11.4.0 for Varbase Media Demo Assets

Problem/Motivation

On the 10.1.x branch, both composer.json and varbase_media_demo.info.yml still pin Drupal core to ~11.3.0, while every sibling varbase_* module on the 10.1.x line has already moved to ~11.4.0.

This makes a fresh Varbase 10.1.x-dev (Drupal 11.4) build unable to resolve drupal/varbase_media_demo:dev-10.1.x. Composer silently falls back to the stale 10.1.0-alpha1 tag, which ships the old dead-Vimeo demo content and breaks fresh installs at media oEmbed validation.

Steps to reproduce

1. Require drupal/varbase_media_demo:dev-10.1.x on a Varbase 10.1.x-dev site pinned to Drupal core ~11.4.0.
2. Composer cannot satisfy drupal/core: ~11.3.0 from varbase_media_demo against the site's ~11.4.0 constraint, and falls back to the released 10.1.0-alpha1 tag.
3. Installing that tag ships the old dead-Vimeo demo content, which fails media oEmbed validation on install.

Proposed resolution

Bump the Drupal core requirement in both files on the 10.1.x branch to match the rest of the suite:

• composer.json: "drupal/core": "~11.3.0" → "~11.4.0"
• varbase_media_demo.info.yml: core_version_requirement: ~11.3.0 → ~11.4.0

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 varbase_media_demo-10.1.1

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• N/A