Navigation block placeholder is invisible against black a background

[kjellr]

If you place the navigation block on top of a blank background, its deselected placeholder is invisible:

To reproduce:

<!-- wp:group {"style":{"color":{"background":"#000000"}}} -->
<div class="wp-block-group has-background" style="background-color:#000000"><!-- wp:navigation {"orientation":"horizontal"} /--></div>
<!-- /wp:group -->

Seen in a few block based themes, incl. TT1 Blocks and emptytheme.

[kjellr]

cc @jasmussen since I know you've been iterating on this placeholder. I see that it's supposed to pick up the currentColor, but it doesn't seem to be working for me in this case.

This issue comes up in a few of the patterns in #31610:

Both of those have nav block placeholders on the right side, but they're impossible to see. I expected something more like this:

[jasmussen]

Thanks for the ping, I'll take a look as soon as I get a moment. It might be an effect of the recently merged burger menu.