feat: rewrite collab server connecting (#4881)

Co-authored-by: dwelle <luzar.david@gmail.com>

src/excalidraw-app/data/index.ts

@@ -30,7 +30,25 @@ const generateRoomId = async () => {
   return bytesToHexString(buffer);
 };
 
-export const SOCKET_SERVER = process.env.REACT_APP_SOCKET_SERVER_URL;
+/**
+ * Right now the reason why we resolve connection params (url, polling...)
+ * from upstream is to allow changing the params immediately when needed without
+ * having to wait for clients to update the SW.
+ */
+export const getCollabServer = async (): Promise<{
+  url: string;
+  polling: boolean;
+}> => {
+  try {
+    const resp = await fetch(
+      `${process.env.REACT_APP_PORTAL_URL}/collab-server`,
+    );
+    return await resp.json();
+  } catch (error) {
+    console.error(error);
+    throw new Error(t("errors.cannotResolveCollabServer"));
+  }
+};
 
 export type EncryptedData = {
   data: ArrayBuffer;