Describe the bug
In the current version of Gutenberg (8.3.0) and several earlier versions, block patterns display even if the blocks they are composed of are not "allowed" on the post type (via the allowed_block_types filter). Patterns should be hidden if they are composed of disallowed blocks.

To reproduce
Steps to reproduce the behavior:

1. Create a post type
2. Use allowed_block_types filter to limit blocks down to one or two
3. Observe patterns displaying

Expected behavior
Patterns should only display if all their constituent blocks are available.

Screenshots