Consent layer gets longer than viewport height

[Kirby]

Affected version

2.2.12

Due to legal requirements we wolud most likely have to make phrase cookie_consent_description a bit longer than the default.
Unfortunately if we do that, the layer covers the whole screen on mobile and doesn't even show the action buttons above the fold.



This should be changed so the layer never gets longer than the max viewport height, no matter how long the phrase is.