fixup! test(send queue): add more tests for cancellation

crates/matrix-sdk/tests/integration/send_queue.rs

@@ -2343,6 +2343,9 @@ async fn test_cancel_upload_with_uploaded_thumbnail_and_file_active() {
     // The thumbnail uploads just fine.
     assert_update!(watch => uploaded { related_to = upload_txn, mxc = mxc_uri!("mxc://sdk.rs/thumbnail") });
 
+    // Let the file upload request start.
+    sleep(Duration::from_millis(500)).await;
+
     // Abort the upload.
     abort_and_verify(&client, &mut watch, img_content, upload_handle, upload_txn).await;