[Lens] Dropping numerical field into dimension wrongly select Minimum aggregation

[timroes]

If you drop a numerical field into the workarea of Lens, it will correctly be added as a y-axis dimension with Average aggregation. If you drop it directly into an empty slot of the dimension panel, it will instead use Minimum. This is a bug, and it should use Average everywhere.

[elasticmachine]

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

[wylieconlon]

Blocked by #58279

[wylieconlon]

Now unblocked, but I don't think the fix is patch-worthy because the drop behavior has always worked this way. I agree that we should change the drop behavior because it feels wrong, but it requires some updates to the suggestion system.