LibWeb: Style font-variant-* css properties

Author: https://github.com/jdahlin
Commit: 1c42d6831b
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2197
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/gmta ✅
Reviewed-by: https://github.com/kalenikaliaksandr
Reviewed-by: https://github.com/tcl3

Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-all-supported-properties-and-default-values.txt

@@ -1,6 +1,6 @@
 All supported properties and their default values exposed from CSSStyleDeclaration from getComputedStyle:
 'cssText': ''
-'length': '206'
+'length': '212'
 'parentRule': 'null'
 'cssFloat': 'none'
 'WebkitAlignContent': 'normal'
@@ -305,6 +305,20 @@ All supported properties and their default values exposed from CSSStyleDeclarati
 'font-style': 'normal'
 'fontVariant': 'normal'
 'font-variant': 'normal'
+'fontVariantAlternates': 'normal'
+'font-variant-alternates': 'normal'
+'fontVariantCaps': 'normal'
+'font-variant-caps': 'normal'
+'fontVariantEastAsian': 'normal'
+'font-variant-east-asian': 'normal'
+'fontVariantEmoji': 'normal'
+'font-variant-emoji': 'normal'
+'fontVariantLigatures': 'normal'
+'font-variant-ligatures': 'normal'
+'fontVariantNumeric': 'normal'
+'font-variant-numeric': 'normal'
+'fontVariantPosition': 'normal'
+'font-variant-position': 'normal'
 'fontVariationSettings': 'normal'
 'font-variation-settings': 'normal'
 'fontWeight': '400'