fix(HTTP Request Node): Duplicate key names support for form data (#9040)

Co-authored-by: Marcus <marcus@n8n.io>

packages/nodes-base/nodes/HttpRequest/GenericFunctions.ts

@@ -7,7 +7,13 @@ import type {
 
 import set from 'lodash/set';
 
-export type BodyParameter = { name: string; value: string };
+import FormData from 'form-data';
+
+export type BodyParameter = {
+	name: string;
+	value: string;
+	parameterType?: 'formBinaryData' | 'formData';
+};
 
 export type IAuthDataSanitizeKeys = {
 	[key: string]: string[];
@@ -168,6 +174,22 @@ export const prepareRequestBody = async (
 			set(result, entry.name, entry.value);
 			return result;
 		}, Promise.resolve({}));
+	} else if (bodyType === 'multipart-form-data' && version >= 4.2) {
+		const formData = new FormData();
+
+		for (const parameter of parameters) {
+			if (parameter.parameterType === 'formBinaryData') {
+				const entry = await defaultReducer({}, parameter);
+				const key = Object.keys(entry)[0];
+				const data = entry[key] as { value: Buffer; options: FormData.AppendOptions };
+				formData.append(key, data.value, data.options);
+				continue;
+			}
+
+			formData.append(parameter.name, parameter.value);
+		}
+
+		return formData;
 	} else {
 		return await reduceAsync(parameters, defaultReducer);
 	}