What to do about entity deletion order in command flushes?

## What problem does this solve or what need does it fill?

I recently ran into a crash because I inserted a component that was despawned in the same stage (and presumably the same issue would be present with an explicit flush in stageless). The fix was to order my systems so that the insert happens first and then the despawn happens.

## What solution would you like?

I don't really see the point of crashing when there's already a check at insert time to make sure the component exists. If this is intentional, then I think the ambiguity reporter should understand Commands conflicts.

## Additional context

I'm on my phone rn, can add stack trace if needed later.