approx_distinct should be leveraging dictionary encoding to support faster counting for these types

[jimexist]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

A challenge to improve approx_distinct, which should be leveraging dictionary encoding to support faster counting for these types.

Describe the solution you'd like

Making sure we can use the cardinality of the dictionary to speed up.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[jimexist]

related #1109