[BUGFIX] Render smallRetina sourceCollection in image CType

The smallRetina sourceCollection is rendered for any
layoutKey constant other than "default".

Resolves: #52991
Releases: 6.2
Change-Id: I63881b08e46d2b9d421b284b7d3d5533ca6aa05b
Reviewed-on: https://review.typo3.org/24917
Reviewed-by: Steffen Müller
Tested-by: Steffen Müller