OpenQuake Data Viewer Labels for Aggregate Losses display incorrectly

[alejocaldeGEM]

Issue

In the same event_based_risk.zip from this issue, when the user uses the button Aggregate of the Average Asset Losses output, the OpenQuake Data Viewer displays the losses using labels that are not legible. See the following:

Intended Behavior

Previously, the labels would be displayed correctly, letting the user know that the aggregate losses are per realization (in the case of a single event), or total in the case of an event-based calculation. See below:

[ptormene]

While in scenario calculations there is a 1-to-1 correspondence between realizations and gsims, in event-based things are a lot more complex. See https://docs.openquake.org/oq-engine/advanced/master/logic_trees.html?highlight=realizations#the-logic-tree-demo
We need to discuss what we want to visualize. @micheles and I propose to postpone this after the release.