Advanced hunting: Only return columns that contain values

gistfile1.txt

<Query>
| extend values = pack_all()
| mv-apply values on 
(
    mv-expand kind = array  values
    | where isnotempty(values[1])
    | summarize EmptyValuesRemoved = make_bag(pack(tostring(values[0]), values[1]))
)
| project EmptyValuesRemoved
| evaluate bag_unpack(EmptyValuesRemoved)


// credits: https://stackoverflow.com/questions/66414407/is-it-possible-in-kusto-to-only-return-columns-with-values