[Lens] Datatable without metric column shows no results

[mbondyra]

Kibana version:
master

Describe the bug:
For lens data table visualization, when there are only bucketed columns defined, table shows no results:

Expected behavior:

1. We could show error that it cannot be rendered and metric value is needed
   or
2. We implicitly assume that 'count of records' is the value for buckets to refer to

[mbondyra]

Checking it now it works better by showing the error:

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[wylieconlon]

I think it makes sense to have an implicit "count" in the aggregation- I think this is something we can control inside our data source. It would also help solve a related issue, which is that the sort order of the Terms aggregation is set to "alphabetical" when there is no metric, even though that's not as useful as sorting Terms by Count.

[flash1293]

As this is a general thing, would it make sense to solve it in esaggs instead?

[wylieconlon]

Opened a new issue for the fix on esaggs, but I think we may also want to work around this in the code that we control.

[flash1293]

This is handled much better in the current version:

Closing - if something thinks something else should be done about this, feel free to re-open