Move buttons are hard to use within a nested block

[shaunandrews]

Describe the bug
Using a meda+text block, its hard to move the paragraphs around without actually focusing on them — the move buttons appear when hovered, but you can't actually interact with them. Here's a GIF that hopefully helps you understand the problem:

Alternatively, sometimes the opposite is true — the move buttons get in the way of resizing the image. Here's another GIF:

The behavior seems to change depending on what block you currently have focused, but I can't seem to understand the logic behind the change.

[mapk]

Talked about this in today's design triage.

Let's explore an option to only show the move icons when the block is selected. Although I feel like this is a workaround, it may be the workaround we need. A try/ PR could help communicate this.

Related: #16718 and kind of #16646

[mapk]

Another related issue with weirdness around these controls:
#16742

[karmatosed]

Another issue with spacer:

[karmatosed]

I think this can be solved as part of the iterations here: #18667

[jasmussen]

Yes, this would definitely be fixed by #18685!