Expose experiment report URL in drupalSettings

[jjroelofs]

Add experimentUrl to drupalSettings for DXPR Builder integration

Linked issues

• Fix Expose experiment report URL in drupalSettings for DXPR Builder integration #22

Summary

• Add experimentUrl to the drupalSettings.aiSorting.views output
• URL is generated using Drupal's routing system via Url::fromRoute()
• Consuming modules can now link to experiment reports without hardcoding URL structure

Test plan

• Enable ai_sorting on a View
• Check drupalSettings.aiSorting.views in browser console
• Verify experimentUrl is present and points to correct report page

Checklist

• I have read the CONTRIBUTING.md document.
• My commit messages follow the contributing standards and style of this project.
• My code follows the coding standards and style of this project.
• My code contains no changes that are outside the scope of the issue.
• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).