Fuseki UI: /edit view should not count number of triples for each graph

### Version

4.7.0

### Feature

The "edit" view at `/#/dataset/NAME/edit` is barely usable for large sets of graphs because the number of triples is counted for each graph, a time-consuming query. The number of triples should better be requested only if a graph is selected or only for a few graphs when paging through the list of graphs.

### Are you interested in contributing a solution yourself?

No

Start at the Fuseki UI entry point `/#/dataset/NAME/edit` and trace how the graph list requests triple counts. Confirm the behavior with a dataset containing many graphs, then verify that counts are requested only for a selected graph or the small visible page of graphs.

Written by the indexing model from the issue text.