Mattermost: avoid raw fetch in monitor media download

extensions/mattermost/src/mattermost/monitor.ts

@@ -63,7 +63,6 @@ export type MonitorMattermostOpts = {
   webSocketFactory?: MattermostWebSocketFactory;
 };
 
-type FetchLike = (input: URL | RequestInfo, init?: RequestInit) => Promise<Response>;
 type MediaKind = "image" | "audio" | "video" | "document" | "unknown";
 
 type MattermostReaction = {
@@ -224,12 +223,6 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
     log: (message) => logVerboseMessage(message),
   });
 
-  const fetchWithAuth: FetchLike = (input, init) => {
-    const headers = new Headers(init?.headers);
-    headers.set("Authorization", `Bearer ${client.token}`);
-    return fetch(input, { ...init, headers });
-  };
-
   const resolveMattermostMedia = async (
     fileIds?: string[] | null,
   ): Promise<MattermostMediaInfo[]> => {
@@ -242,7 +235,11 @@ export async function monitorMattermostProvider(opts: MonitorMattermostOpts = {}
       try {
         const fetched = await core.channel.media.fetchRemoteMedia({
           url: `${client.apiBaseUrl}/files/${fileId}`,
-          fetchImpl: fetchWithAuth,
+          requestInit: {
+            headers: {
+              Authorization: `Bearer ${client.token}`,
+            },
+          },
           filePathHint: fileId,
           maxBytes: mediaMaxBytes,
         });