Adds a transform.to to the JS block registration of the custom collapsable block to allow it to be changed to a core/details block while retaining the attributes and innerBlocks
Steps to test:
Edit a post
Add a collapsable block (This is now hidden from the block inserter so will need to be added via code editor )
Save the post and refresh, now click the block icon in the block toolbar and notice Details appears in the transform options
Click Details in the options and the collapsable block should change to a Details block while retaining all the content and attributes
Ref: https://github.com/amnestywebsite/humanity-theme/issues/229
Adds a transform.to to the JS block registration of the custom collapsable block to allow it to be changed to a core/details block while retaining the attributes and innerBlocks
Steps to test:
Example: http://bigbite.im/v/vVSMnE