LibWeb/IDL: Always throw an error if string does not match an enum value

Previously we only threw an error if the enum was used as a function
argument. However, we are supposed to throw an error no matter the
context it is used in.

Meta/Lagom/Tools/CodeGenerators/LibWeb/WrapperGenerator/IDLGenerators.cpp

@@ -265,7 +265,7 @@ static bool should_emit_wrapper_factory(IDL::Interface const& interface)
 }
 
 template<typename ParameterType>
-static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter, String const& js_name, String const& js_suffix, String const& cpp_name, IDL::Interface const& interface, bool legacy_null_to_empty_string = false, bool optional = false, Optional<String> optional_default_value = {}, bool variadic = false, size_t recursion_depth = 0, bool used_as_argument = false)
+static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter, String const& js_name, String const& js_suffix, String const& cpp_name, IDL::Interface const& interface, bool legacy_null_to_empty_string = false, bool optional = false, Optional<String> optional_default_value = {}, bool variadic = false, size_t recursion_depth = 0)
 {
     auto scoped_generator = generator.fork();
     auto acceptable_cpp_name = make_input_acceptable_cpp(cpp_name);
@@ -592,8 +592,7 @@ static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter
 )~~~");
         }
 
-        if (used_as_argument) {
-            enum_generator.append(R"~~~(
+        enum_generator.append(R"~~~(
     @else@
         return vm.throw_completion<JS::TypeError>(global_object, JS::ErrorType::InvalidEnumerationValue, @js_name.as_string@, "@parameter.type.name@");
 )~~~");
@@ -1218,7 +1217,7 @@ static void generate_arguments(SourceGenerator& generator, Vector<IDL::Parameter
         }
 
         bool legacy_null_to_empty_string = parameter.extended_attributes.contains("LegacyNullToEmptyString");
-        generate_to_cpp(generator, parameter, "arg", String::number(argument_index), parameter.name.to_snakecase(), interface, legacy_null_to_empty_string, parameter.optional, parameter.optional_default_value, parameter.variadic, 0, true);
+        generate_to_cpp(generator, parameter, "arg", String::number(argument_index), parameter.name.to_snakecase(), interface, legacy_null_to_empty_string, parameter.optional, parameter.optional_default_value, parameter.variadic, 0);
         ++argument_index;
     }