Return Bokeh histograms for the job list, loaded incrementally.

This endpoint supports per-plot loading for metric histograms. The caller must provide a 'group' query parameter:

• group=metric&metric=<name>: return a single metric histogram (thumb and full) for the given metric name.

Args: request (Any): Request passed to this helper.

Returns: Any: Value produced by this call (type depends on inputs).

Examples:

job_list_histograms(None) # doctest: +SKIP