LibWeb: Parse and propagate white-space-trim CSS property

Author: https://github.com/Calme1709
Commit: 9480b1fc5c
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4832
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/gmta ✅

Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-has-indexed-property-getter.txt

@@ -233,10 +233,11 @@ All properties associated with getComputedStyle(document.body):
     "230": "user-select",
     "231": "vertical-align",
     "232": "view-transition-name",
-    "233": "width",
-    "234": "x",
-    "235": "y",
-    "236": "z-index"
+    "233": "white-space-trim",
+    "234": "width",
+    "235": "x",
+    "236": "y",
+    "237": "z-index"
 }
 All properties associated with document.body.style by default:
 {}

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

@@ -650,6 +650,8 @@ All supported properties and their default values exposed from CSSStylePropertie
 'white-space': 'normal'
 'whiteSpaceCollapse': 'collapse'
 'white-space-collapse': 'collapse'
+'whiteSpaceTrim': 'none'
+'white-space-trim': 'none'
 'width': '284px'
 'wordBreak': 'normal'
 'word-break': 'normal'

Tests/LibWeb/Text/expected/css/getComputedStyle-print-all.txt

@@ -231,6 +231,7 @@ unicode-bidi: normal
 user-select: auto
 vertical-align: baseline
 view-transition-name: none
+white-space-trim: none
 width: 784px
 x: 0px
 y: 0px

Tests/LibWeb/Text/expected/css/white-space-trim.txt

@@ -0,0 +1,3 @@
+none
+discard-inner
+discard-after discard-inner