Add `type: array, items: { type: string }` test-only SDC, to prove "Tags" field can be linked

Overview

🐛 Editing support for type: array Active added type: array support, and added the image-gallery (single caption + array of images) and sparkline (array of integers between -100 and 100) test SDCs.

A much more common use case is an array of entity labels that are referenced. For example: the "tags" field. Which is what #3552918: Blog post tags don't appear in Canvas as potential field → explicitly is calling out as a bug, when it is not. (And ✨ Support linking field types marked SUPPORTED from #3512433 to props in a `ContentTemplate` Active before it.)

⚠️ Note that this is essentially blocked on 🐛 Editing support for type: array Active , because without that, it'll still be a broken experience overall, because the field widget-based editing experience (using the default StaticPropSource's field widget) will not work without it.

Proposed resolution

1. ✅ Add a test-only
2. Prove it provides the appropriate suggestions when building a ContentTemplate: Standard install profile's "Tags" field appears.

User interface changes

None.