Revert "Updating the undici Major Version (Azure#350)"

This reverts commit c543818.

The support range for undici in newer versions does not match the
current @azure/functions support range.

The original commit broke Node.js 18 support, due to unidici 7 only
supporting Node.js 20 and above. Latest undici supports >=18.17,
while the latest undici release that had full Node.js 18 support is
v6.13.0. Since v6.13.0 has known security issues, it's just a plain
revert.

Author: BridgeAR

package-lock.json

@@ -1,6 +1,6 @@
 {
     "name": "@azure/functions",
-    "version": "4.7.3",
+    "version": "4.7.4",
     "description": "Microsoft Azure Functions NodeJS Framework",
     "keywords": [
         "azure",
@@ -43,7 +43,7 @@
     "dependencies": {
         "cookie": "^0.7.0",
         "long": "^4.0.0",
-        "undici": "^7.10.0"
+        "undici": "^5.29.0"
     },
     "devDependencies": {
         "@types/chai": "^4.2.22",

package.json

@@ -1,6 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License.
 
-export const version = '4.7.3';
+export const version = '4.7.4';
 
 export const returnBindingKey = '$return';

src/constants.ts

@@ -96,7 +96,6 @@ export class HttpRequest implements types.HttpRequest {
     }
 
     async formData(): Promise<FormData> {
-        // eslint-disable-next-line deprecation/deprecation
         return this.#uReq.formData();
     }
 

src/http/HttpRequest.ts

@@ -63,7 +63,6 @@ export class HttpResponse implements types.HttpResponse {
     }
 
     async formData(): Promise<FormData> {
-        // eslint-disable-next-line deprecation/deprecation
         return this.#uRes.formData();
     }
 

src/http/HttpResponse.ts

@@ -5,6 +5,7 @@ import 'mocha';
 import * as chai from 'chai';
 import { expect } from 'chai';
 import * as chaiAsPromised from 'chai-as-promised';
+import { File } from 'undici';
 import { HttpRequest } from '../../src/http/HttpRequest';
 
 chai.use(chaiAsPromised);
@@ -134,7 +135,7 @@ value2
             const contentTypes = ['application/octet-stream', 'application/json', 'text/plain', 'invalid'];
             for (const contentType of contentTypes) {
                 const req = createFormRequest('', contentType);
-                await expect(req.formData()).to.eventually.be.rejectedWith(/Content-Type was not one of /i);
+                await expect(req.formData()).to.eventually.be.rejectedWith(/Could not parse content as FormData/i);
             }
         });
     });