[6.x] Forms 2: Compressed view

[jaygeorge]

Description of the Problem

The "compressed view" for forms is sort of the same idea really as the regular blueprint editing view.
I think it's better to bridge this gap and make it feel very similar for a few reasons:

• Consistency across the CP / adhering to known affordances
• If we roll out the three column paradigm later on to regular blueprints then things slot together more nicely

What this PR Does

Makes the "compressed" view closer to that of the v6 regular blueprint
Adds a helper data attribute

Before

After

FYI I think this looks better when things get messier:

Before

After

How to Reproduce

1. Click the "compressed view" button when editing a form