When painting in the image editor on data images (Non-color, Raw) the
color mismatched between the sampled color and the actual effect that
the painting has on the image. The root cause is that the sampling is
color managed, but the painting still uses a fixed color management
pipeline with a lot of assumptions. Due to recent changes the drawing
of the image editor is color managed, but the painting isn't what made
these changes show up.

This patch is a work-a-round so that the sampled colors and the effect
the paint has on the texture matches. This isn't the correct solution
as that would be to migrate all the painting tools to use proper color
management.