gatsby-plugin-image constrained should not use breakpoints

[laurenskling]

Constrained images use the outputPixelDensities feature. That feature clearly states: Ignored for full width layout images, which use breakpoints instead.
So I find it strange that constrained images actually do use the breakpoints feature. I noticed this when I set default breakpoints in the gatsby-plugin-sharp options.

As I am writing this, I actually found out that my constrained image is not using the outputPixelDensities because of my default breakpoints. It is only slicing the width I request and the breakpoint widths.