Fix: recalculate the palette condition for extended palettes derived from default palette.
Remove code redundance: recalculate only in one place.
Fix: recalculate the palette condition for extended palettes derived from default palette.
Remove code redundance: recalculate only in one place.
Merge branch 'fix-palette-condition' of github.com:discordier/contao-meta-palettes into fix-palette-condition
Further fix for palette extending - always recalculate the palette condition.

This is needed as otherwise the selector will be taken as select value into account when
extending via empty subpalettes.
Merge pull request #19 from discordier/fix-palette-condition

Recalculate the palette condition when deriving from default palette.