Bug 1539378 - personality provider update (#5068)

lib/PersonalityProvider.jsm

@@ -24,7 +24,7 @@ XPCOMUtils.defineLazyGetter(this, "gTextDecoder", () => new TextDecoder());
 
 XPCOMUtils.defineLazyGetter(this, "baseAttachmentsURL", async () => {
   const server = Services.prefs.getCharPref("services.settings.server");
-  const serverInfo = await (await fetch(`${server}/`)).json();
+  const serverInfo = await (await fetch(`${server}/`, {credentials: "omit"})).json();
   const {capabilities: {attachments: {base_url}}} = serverInfo;
   return base_url;
 });