What?

Resolves: #46367
Maybe alternative of: #46369

Currently in Query Loop set up flow a user can choose to start blank, where the scoped block variations are suggested. If extenders of Query Loop have added scoped inserter variations(ex List of Products) and choose to start blank the default block variations will be suggested, which might make no sense or just unwanted.

For such inserter variations there is already in place the mechanism to suggest connected patterns. So this PR implements something similar for connected scoped block patterns to other Query Loop variations(inserter).

I have used a convention:

Helper hook that determines if there is an active variation of the block
and if there are available specific scoped block variations connected with
this variation.
If there are, these variations are going to be the only ones suggested
to the user in setup flow when clicking to start blank, without including
the default ones for Query Loop.
If there are no such scoped block variations, the default ones for Query
Loop are going to be suggested.
The way we determine such variations is with the convention that they have the namespace
attribute defined as an array. This array should contain the names(name property) of any
variations they want to be connected to.
For example, if we have a Query Loop scoped inserter variation with the name products,
we can connect a scoped block variation by setting its namespace attribute to ['products'].
If the user selects this variation, the namespace attribute will be overridden by the
main inserter variation.

but that was my quick first thought for the implementation and can be adjusted..

In general scoped block variation are meant to be a simple starting point that usually

Testing Instructions

 {
		description: 'Variation',
		name: 'variation_query_loop',
		title: 'Variation Query Loop',
		icon: 'admin-home',
		attributes: {
			displayLayout: {
				type: 'flex',
				columns: 3,
			},
			namespace: 'inserter_namespace_variation_query_loop',
			query: {
				perPage: 9,
				pages: 0,
				offset: 0,
				postType: 'page',
				order: 'desc',
				orderBy: 'date',
				author: '',
				search: '',
				exclude: [],
				sticky: '',
				inherit: false,
			},
		},
		isActive: [ 'namespace' ],
		scope: [ 'inserter' ],
	},
	{
		description: 'Connected Variation',
		name: 'connected-block-variation',
		title: 'Connected Variation',
		icon: 'admin-home',
		attributes: {
			displayLayout: {
				type: 'flex',
				columns: 3,
			},
			namespace: ['variation_query_loop'], // This is the same with the `name` of the variation to be 'connected'
			query: {
				perPage: 1,
				pages: 0,
				offset: 0,
				postType: 'page',
				order: 'desc',
				orderBy: 'date',
				author: '',
				search: '',
				exclude: [],
				sticky: '',
				inherit: false,
			},
		},
		innerBlocks: [
			[
				'core/post-template',
				{},
				[ [ 'core/post-title' ], [ 'core/post-date' ] ],
			],
		],
		scope: [ 'block' ],
	},

1. Insert Query Loop block and any different variations(like the one provided above)
2. Choose to start blank

Notes

Would we need to support scoped block variations to be connected to more than one inserter variation?

Screenshots or screencast