Feature request: Add support for add_ci() with tbl_summary(percent = c('row', 'cell'))

[ddsjoberg]

We will also need to support add_ci.tbl_svysummary()

[ddsjoberg]

I started implementing this in add_ci.tbl_summary(). In the current construct, 'cell' would be pretty tricky to implement, but 'row' is somewhat reasonable...but requires some gross manipulation to the current code.

This would be best implemented in cardx::ard_categorical_ci(). I've opened an issue here insightsengineering/cardx#204