Anchor tags are returning null for custom ACF blocks

[brysonchiu]

I origonally opened this ticket, https://github.com/wp-graphql/wpgraphql-acf/issues/204, but Jason Bahl directed me to open one here instead.

Steps to reproduce

1. Create a ACF block type and enable anchor attribute in the block type settings under the "Supports" tab.
2. Add the block to a page and include an anchor to the block.
3. Query:

query NewQuery {
  page(id: "/[PAGE-PATH]", idType: URI) {
    editorBlocks {
      ... on [BLOCK] {
        attributes {
          anchor
        }
      }
    }
  }
}

Anchors work for core blocks, but not for ACF blocks