tbl_continuous() without by doesn't have the header N in the ARD

[ddsjoberg]

I wonder if I should incorporate the total N ARD from cards cards::ard_total_n()? We could add this to all the summary tbls?

We want to be able to remove this line from tbl_ard_continuous() (and similar code from ard_continuous())

  # if `by` is missing, then remove Ns since they are not in the ARD by default
  if (is_empty(by)) {
    x$table_styling$header <- x$table_styling$header |>
      dplyr::mutate(across(c("modify_stat_N", "modify_stat_n"), ~NA_integer_))
  }