Extra <br /> tags in information screen item preview

[wwqrd]

On the information screen multiple new lines for a text block are shown as
tags in the item preview. This is stripped when rendered in Interviewer (preview), and also parses correctly into a new line in the rich text editor. Seems like something the rich text serializer is doing.

• Update the preview (in the list in architect) to match the render settings in Interviewer
• Update the serializer to remove this behaviour?

[wwqrd]

react-markdown escapes html intentionally for security reasons. remark-slate serializes multiple line breaks into
tags.

Options are:

• Add html support to react-markdown (security implication with malicious protocols)
• Strip <br> tags from the serialized output (will cause mismatch between <RichText> preview and actual markdown output)
• Replace <br> tags in output with something that react-markdown supports. It's not clear if there is something suitable; double spaces only work when used in conjunction with copy.
• Update the slate instance to prevent multiple line breaks (may seem like broken behaviour to user)

[jthrilly]

I don't think we should be generating <br /> tags from slate, so my first preference is to prevent that. Maybe we could replace them with empty paragraphs that contain a single (escaped) space. This would require updating the empty node detection.

Failing that, I think stripping them and accepting the mismatch between the editor and the output is the thing to do.

[rebeccamadsen]

I think this was resolved in #728. Or at least I can't replicate this now.