Screen Recording 2023-03-13 at 14.13.32.mov

Looks like when multiple stages are removed quickly, an empty stage that cannot be interacted with can exist in the pipeline.

This is a bit harder to do now than before as the remove stage button is now in a menu, however it still should be able to happen.

My hunch as to what's happening is a race condition with loading the preview. We probably want to ignore preview results when the underlying pipeline has changed and they are no longer relevant.

Reported on slack:
https://mongodb.slack.com/archives/C0U7K0MC3/p1678713461139429