Do not check if value of `ref` key exists in presets

[Woazboat]

The validator currently checks the value of ref=* against presets and displays an information level hint "Presets do not contain property value - Value '<some value>' for key 'ref' not in presets".
The value of ref could be anything (similar to name=*), so it doesn't make sense to check it against a set of predefined values..

[Klumbumbus]

In 18676/josm:

fix #22761 - Don't warn about "Value '<some value>' for key 'ref' not in presets"

[Klumbumbus]

The error didn't appear in JOSM core by default because the internal preset doesn't include a combo for the key ref, so it was only reproducible with an external preset.

[Woazboat]

ty
No idea which of my installed presets has that, but that would explain it

[skyper]

Replying to Woazboat:

The value of ref could be anything (similar to name=*), so it doesn't make sense to check it against a set of predefined values.

Exactly, and as values are unique it does not make sense to offer values for both.