Description of the Problem

There are a couple of problems with the spacer field at lower viewports, described here #13983

• Firstly the spacer field type has some hidden text which can make the field appear taller than standard fields at smaller viewports when the invisible text is wrapped.
• Secondly the spacer field should collapse at mobile-like viewports where we use a stacked layout. Currently it causes a vertical gap.

What this PR Does

• Avoid rendering the "Component does not exist" text
• Hides the spacer fieldtype completely for smaller viewports where the stacked layout is used
• Closes Spacer fieldtype should collapse in stacked layouts (small screen sizes) #13983

Taller Spacer Field (Before)

The spacer fieldtype had some extra text which meant it was "taller" than other fields at smaller viewports. Here it is around 78px vs the 66px height of a standard field, causing the row here to be taller than usual.

Taller Spacer Field (After)

The spacer should now be no taller than the other fields (66px here)

Gap (Before)

Gap (After)

How to Reproduce

1. As per Spacer fieldtype should collapse in stacked layouts (small screen sizes) #13983 add some 33% fields with a 33% field with spacer, like so:

2. Reduce the viewport width and see the problems listed above