Issue #170 wrap paragraph text in preview

[herbdool]

Fixes #170

[herbdool]

@laryn I'm reopening this, because now I can't find a paragraphs-item class and it doesn't seem to be doing it on my test install. Maybe it should just be this instead so it directly overrides the line in core:

.field-widget-paragraphs-embed table .form-item {
  white-space: normal;
}

At least until there's a fix in core.

[herbdool]

I also added a PR for core: backdrop/backdrop-issues#6365