Template JSON needs check for missing static block in Liquid file

Describe the bug

There's no error in a template JSON when a static block is referenced that the section/block never includes.

This type of check does exist in the SchemaPresetsStaticBlocks and ValidBlockTarget check; however, if a dev is not using presets, the issue won't be known.

Reproduction

Have a block that includes a static block with content_for 'block'; e.g. a _collection-card-image. And use it in a preset.

# blocks/collection-card.liquid

{% content_for 'block', type: '_collection-card-image', id: 'collection-card-image', %}

{% schema %}
{
  "name": "t:names.collection_card",
  "blocks": [...],
  "settings": [...]
  ],
  "presets": [
    {
      "name": "t:names.collection_card",
      "blocks": {
        "collection-card-image": {
          "type": "_collection-card-image",
          "static": true,
        }
    }
  ]
}
{% endschema %}

• Have this block referenced in a template JSON, like index.json.

• Delete the content_for 'block' referenc

Expected behaviour

The SchemaPresetsStaticBlocks check successfully runs and warns me.

Static block collection-card-image is missing a corresponding content_for "block" tag.

The ValidBlockTarget is also helpful

Could not find a static block of type "_collection-card-image" with id "collection-card-image" in this file.theme-checkValidBlockTarget

I expect a similar warning in index.json

Actual behaviour

No warning in index.json

Having no presets illustrates that theme dev isn't given any warnings the contents of index.json are a problem.

Debugging information

• OS Mac
• Theme Check Version 3.16.1

Start by comparing the existing SchemaPresetsStaticBlocks and ValidBlockTarget checks, then trace how template JSON files such as index.json are validated. Add equivalent detection for static blocks referenced from template JSON and verify that the missing content_for "block" case produces the expected warning.