Enable CSSColorMixEnabled and CSSGradientInterpolationColorSpacesEnab…

…led preference

https://bugs.webkit.org/show_bug.cgi?id=242917
<rdar://97278994>

Reviewed by Myles C. Maxfield.

CSSWG thinks these features are ready to ship: w3c/csswg-drafts#7310 (comment)

* Source/WTF/Scripts/Preferences/WebPreferencesExperimental.yaml:

Canonical link: https://commits.webkit.org/252716@main

Source/WTF/Scripts/Preferences/WebPreferencesExperimental.yaml

@@ -230,11 +230,11 @@ CSSColorMixEnabled:
   humanReadableDescription: "Enable support for CSS color-mix() defined in CSS Color 5"
   defaultValue:
     WebKitLegacy:
-      default: false
+      default: true
     WebKit:
-      default: false
+      default: true
     WebCore:
-      default: false
+      default: true
 
 CSSContainIntrinsicSizeEnabled:
   type: bool
@@ -314,11 +314,11 @@ CSSGradientInterpolationColorSpacesEnabled:
   humanReadableDescription: "Enable custom interpolation in CSS gradients"
   defaultValue:
     WebKitLegacy:
-      default: false
+      default: true
     WebKit:
-      default: false
+      default: true
     WebCore:
-      default: false
+      default: true
 
 CSSGradientPremultipliedAlphaInterpolationEnabled:
   type: bool