Gutenberg: annotations don't appear

[contactashish13]

Annotations don’t work in the Gutenberg editor, they appear only on front-end
https://prnt.sc/ql778v
https://prnt.sc/ql77hl
https://prnt.sc/ql77m7

[contactashish13]

PR #615 adds a message under charts that have annotations. The message reads Annotations in this chart may not display here but they will display in the front end.