Cleanup in azure_upload_download_works test (#5636)

The `azure_upload_download_works` test is not cleaning up after itself,
leaving behind the files it is uploading. I found these files when
looking at the contents of the bucket in #5627.

We now clean up the file we uploaded before, like the other tests do it
as well.

Follow-up of #5546

libs/remote_storage/tests/test_real_azure.rs

@@ -267,6 +267,12 @@ async fn azure_upload_download_works(ctx: &mut MaybeEnabledAzure) -> anyhow::Res
     let buf = download_and_compare(dl).await?;
     assert_eq!(buf, data);
 
+    debug!("Cleanup: deleting file at path {path:?}");
+    ctx.client
+        .delete(&path)
+        .await
+        .with_context(|| format!("{path:?} removal"))?;
+
     Ok(())
 }