Gutenberg: Vertical navigation block is missing a class on the front

[carolinan]

Describe the bug
In the editor, the vertical variation of the navigation block can be identified with
is-vertical but this CSS class is not present on the front, so there is no way to tell the
horizontal and vertical styles from the other.

To reproduce
Steps to reproduce the behavior:

1. Add a vertical navigation block to a post or page
2. Add a horizontal navigation block too, in case you wish to compare them.
3. Save
4. View the front

Expected behavior
I expect the CSS class and the existing styles to be applied to block.

Screenshots

Editor version (please complete the following information):

• WordPress version: 5.4
  Gutenberg 7.9.1

Desktop (please complete the following information):

• OS: win 10
• Browser: Chrome Version 81.0.4044.122

[karmatosed]

Great catch @carolinan as that makes sense for me too.

[talldan]

Just changing this to a bug as currently the editor and front end versions of the block don't match (Navigation (vertical) is displayed horizontally in the post, but vertically in the editor) due to the missing classname.

[strarsis]

Edit: Current workaround:
Add is-horizontal or is-vertical as extra CSS class to each navigation blocks.