Fix out-of-order execution for enqueueRetryable (#3919)

Author: schmidt-sebastian

.changeset/long-hornets-scream.md

@@ -0,0 +1,5 @@
+---
+"@firebase/firestore": patch
+---
+
+Fixed a potential issue in our internal queue that could have allowed API calls to be executed out of order.

packages/firestore/src/util/async_queue.ts

@@ -321,8 +321,10 @@ export class AsyncQueue {
    * operations were retried successfully.
    */
   enqueueRetryable(op: () => Promise<void>): void {
-    this.retryableOps.push(op);
-    this.enqueueAndForget(() => this.retryNextOp());
+    this.enqueueAndForget(() => {
+      this.retryableOps.push(op);
+      return this.retryNextOp();
+    });
   }
 
   /**