Remove duplicate logos from preview

[asmundmatzow]

The following logos have been moved from preview til logo, but are still also available as previews. These previews should be removed.

nrk-logo-preview-nrk-1
nrk-logo-preview-nrk-1-on-dark
nrk-logo-preview-nrk-1-on-light
nrk-logo-preview-nrk-1-with-bg
nrk-logo-preview-nrk-2
nrk-logo-preview-nrk-2-on-dark
nrk-logo-preview-nrk-2-on-light
nrk-logo-preview-nrk-2-with-bg
nrk-logo-preview-nrk-3
nrk-logo-preview-nrk-3-on-dark
nrk-logo-preview-nrk-3-on-light
nrk-logo-preview-nrk-3-with-bg
nrk-logo-preview-nrk-nyheter
nrk-logo-preview-nrk-nyheter-on-dark
nrk-logo-preview-nrk-nyheter-on-light
nrk-logo-preview-nrk-nyheter-title-below
nrk-logo-preview-nrk-nyheter-title-below-on-dark
nrk-logo-preview-nrk-nyheter-title-below-on-light
nrk-logo-preview-nrk-nyheter-with-bg