LibJS: Implement Temporal.Now.zonedDateTimeISO()

Author: https://github.com/linusg
Commit: a06bd451d4
Pull-request: https://github.com/SerenityOS/serenity/pull/9160
Reviewed-by: https://github.com/IdanHo ✅

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -414,7 +414,8 @@ namespace JS {
     P(writable)                              \
     P(year)                                  \
     P(years)                                 \
-    P(zonedDateTime)
+    P(zonedDateTime)                         \
+    P(zonedDateTimeISO)
 
 struct CommonPropertyNames {
     PropertyName and_ { "and", PropertyName::StringMayBeNumber::No };