Theme JSON schema: Add position.sticky and dimensions.minHeight properties to settings

[t-hamano]

Related to:

• Theme JSON schema: Add sticky position to settings, minHeight to styles #48948
• Style Engine: Add support for dimensions.minHeight property #45334
• Block schema and block supports docs: Add dimensions and position settings #48057

What?

This PR fixes a problem in the theme.json schema where the following two properties in the settings global property cause validation errors (not arrowed error).

• settings.position.sticky
• settings.dimensions.minHeight

This is probably due to the fact that the key is not determined in the settings > properties.

Testing Instructions

Create the following JSON file, specifying the JSON schema changed by this PR.

{
	"$schema": "https://raw.githubusercontent.com/WordPress/gutenberg/schema/stiky-minheight/schemas/json/theme.json",
	"version": 2,
	"settings": {
		"position": {
			"sticky": true
		},
		"dimensions": {
			"minHeight": true
		},
		"blocks": {
			"core/group": {
				"position": {
					"sticky": true
				},
				"dimensions": {
					"minHeight": true
				}
			}
		}
	}
}

When this file is opened in the code editor, confirm that no validation errors occur for all properties.

[github-actions]

Flaky tests detected in 2706fef.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/4511342470
📝 Reported issues:

• [Flaky Test] allows shift tabbing to the block toolbar from the first block #49025 in /test/e2e/specs/site-editor/writing-flow.spec.js
• [Flaky Test] can create template parts via the block placeholder start blank option #49016 in /test/e2e/specs/site-editor/template-part.spec.js

[andrewserong]

Thanks for fixing this up @t-hamano, sorry I missed this one in the previous PR. Also, thanks for figuring out reliable testing instructions for it, that's working nicely, and I'll keep this in mind when I go to make future updates to the schema.

LGTM! ✨