HTML-safe the data section of DataSet show page

This should address [#41917891], using the code we originally used when showing this data in PredefinedGraphPanes (see https://github.com/concord-consortium/smartgraphs-authoring/commit/3724a6bdcb6ee7103febf92fc031d671c0df1c01#L0L608 for the commit where I removed it).