disable publish for dandisets without an asset summary

[satra]

@mvandenburgh and @jjnesbitt - as stated earlier in the thread, publish should be disabled for any dandiset that has an empty asset summary. i believe we should do a check on current dandisets. there are a few that fall into this situation. we don't want people hitting publish with no asset summary. that's going to break a bunch of expectations.

follow up from #1734

[jjnesbitt]

Thanks for the issue. After #1803 and #1800 are merged, missing asset summaries should be a lot less common. Nonetheless, we can still follow up with a PR that prevents publish if it is still missing at the time of publish.

[satra]

@jjnesbitt - hopefully that can be merged soon. in the meantime, can we run through dandisets and regenerate assets for those that are missing and say they are ready to publish?