LibWeb: Don't crash when an unknown property begins with a single dash

Author: https://github.com/Gingeh
Commit: f38e07e0c5
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5518

Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -1622,7 +1622,7 @@ Optional<StyleProperty> Parser::convert_to_style_property(Declaration const& dec
             property_id = PropertyID::Custom;
         } else if (has_ignored_vendor_prefix(property_name)) {
             return {};
-        } else if (!property_name.bytes_as_string_view().starts_with('-')) {
+        } else {
             dbgln_if(CSS_PARSER_DEBUG, "Unrecognized CSS property '{}'", property_name);
             return {};
         }