Deleting all blocks doesn't remove custom block definitions from block list

[bruh-9000]

Expected Behavior

Deleting all blocks in a sprite should remove all custom block definitions from the flyout

Actual Behavior

Deleting all blocks in a sprite does not remove custom block definitions from the flyout

Steps to Reproduce

Explain what someone needs to do in order to see what's described in Actual behavior above

Steps to reproduce the behavior:

1. Create a new block definition
2. Delete all blocks in the sprite via right click
3. Observe how the custom blocks category in the flyout still has the custom block, but it doesn't work and has no definition or usage

System Details

All