Fix site specific features passed to front-end for simple sites (#39817)

* Add `Current_Plan::get_simple_site_specific_features()` method

* Pass the features for simple sites to the script data

* Create siteHasFeature utility

* Add changelog

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/11432946410

Upstream-Ref: Automattic/jetpack@cc5911c

package.json

@@ -18,7 +18,7 @@
 		"@automattic/jetpack-api": "^0.17.15",
 		"@automattic/jetpack-components": "^0.58.0",
 		"@automattic/jetpack-config": "^0.1.25",
-		"@automattic/jetpack-script-data": "^0.1.2",
+		"@automattic/jetpack-script-data": "^0.1.3-alpha",
 		"@wordpress/base-styles": "5.9.0",
 		"@wordpress/browserslist-config": "6.9.0",
 		"@wordpress/components": "28.9.0",