Comments are not deleted when blocks it's attached to get deleted

[apple502j]

Expected Behavior

If a comment is visually gone, it's logically gone.

Actual Behavior

There is no code deleting the comment when the block gets deleted. However, Blockly does not render comments with blockId if there is no block associated with it, so you cannot see this on the workspace.

Steps to Reproduce

• Add a block
• Right-click it and add comment
• Delete the block
• Export project
• The comment still exists in the JSON

Operating System and Browser

any