Mattermost: avoid raw fetch in monitor media download

src/media/fetch.ts

@@ -27,6 +27,7 @@ export type FetchLike = (input: RequestInfo | URL, init?: RequestInit) => Promis
 type FetchMediaOptions = {
   url: string;
   fetchImpl?: FetchLike;
+  requestInit?: RequestInit;
   filePathHint?: string;
   maxBytes?: number;
   maxRedirects?: number;
@@ -79,7 +80,16 @@ async function readErrorBodySnippet(res: Response, maxChars = 200): Promise<stri
 }
 
 export async function fetchRemoteMedia(options: FetchMediaOptions): Promise<FetchMediaResult> {
-  const { url, fetchImpl, filePathHint, maxBytes, maxRedirects, ssrfPolicy, lookupFn } = options;
+  const {
+    url,
+    fetchImpl,
+    requestInit,
+    filePathHint,
+    maxBytes,
+    maxRedirects,
+    ssrfPolicy,
+    lookupFn,
+  } = options;
 
   let res: Response;
   let finalUrl = url;
@@ -88,6 +98,7 @@ export async function fetchRemoteMedia(options: FetchMediaOptions): Promise<Fetc
     const result = await fetchWithSsrFGuard({
       url,
       fetchImpl,
+      init: requestInit,
       maxRedirects,
       policy: ssrfPolicy,
       lookupFn,