Fix leaves level for `count_occurrences` and `summarize_num_patients`

ref: https://github.com/insightsengineering/rtables/issues/663
code:

basic_table() %>%
  split_cols_by("ACTARM") %>%
  split_rows_by("AEBODSYS", child_labels = "visible") %>%
  summarize_num_patients("USUBJID", # Q: do we need this to be a label row (i.e. content row)?
      .stats = c("unique", "nonunique"),
      .labels = c("Total number of patients with at least one adverse event", "Total number of events")) %>%
  count_occurrences("AEDECOD", .indent_mods = -1L) %>% # Q: do we always need this collapse?
  build_table(ex_adae, alt_counts_df = ex_adsl)

                                                             A: Drug X    B: Placebo   C: Combination
—————————————————————————————————————————————————————————————————————————————————————————————————————
cl A.1                                                                                               
  Total number of patients with at least one adverse event   78 (58.2%)   75 (56.0%)     89 (67.4%)  
  Total number of events                                        132          130            160      
  dcd A.1.1.1.1                                              50 (37.3%)   45 (33.6%)     63 (47.7%)  
  dcd A.1.1.1.2                                              48 (35.8%)   48 (35.8%)     50 (37.9%)  
cl B.1                                                                                               
  Total number of patients with at least one adverse event   47 (35.1%)   49 (36.6%)     43 (32.6%)  
  Total number of events                                         56           60             62      
  dcd B.1.1.1.1                                              47 (35.1%)   49 (36.6%)     43 (32.6%)  
cl B.2                                                                                               
  Total number of patients with at least one adverse event   79 (59.0%)   74 (55.2%)     85 (64.4%)  
  Total number of events                                        129          138            143      
  dcd B.2.1.2.1                                              49 (36.6%)   44 (32.8%)     52 (39.4%)  
  dcd B.2.2.3.1                                              48 (35.8%)   54 (40.3%)     51 (38.6%)  
cl C.1                                                                                               
  Total number of patients with at least one adverse event   43 (32.1%)   46 (34.3%)     43 (32.6%)  
  Total number of events                                         55           63             64      
  dcd C.1.1.1.3                                              43 (32.1%)   46 (34.3%)     43 (32.6%)  
cl C.2                                                                                               
  Total number of patients with at least one adverse event   35 (26.1%)   48 (35.8%)     55 (41.7%)  
  Total number of events                                         48           53             65      
  dcd C.2.1.2.1                                              35 (26.1%)   48 (35.8%)     55 (41.7%)  
cl D.1                                                                                               
  Total number of patients with at least one adverse event   79 (59.0%)   67 (50.0%)     80 (60.6%)  
  Total number of events                                        127          106            135      
  dcd D.1.1.1.1                                              50 (37.3%)   42 (31.3%)     51 (38.6%)  
  dcd D.1.1.4.2                                              48 (35.8%)   42 (31.3%)     50 (37.9%)  
cl D.2                                                                                               
  Total number of patients with at least one adverse event   47 (35.1%)   58 (43.3%)     57 (43.2%)  
  Total number of events                                         62           72             74      
  dcd D.2.1.5.3                                              47 (35.1%)   58 (43.3%)     57 (43.2%)  

Can I ask @clarkliming if dcd * are always NOT indented vs Total number of*?

Note on the problem: pruning out Totals makes dcd * collapse to -1L indentation because the parent node is lost, therefore being on same level of cl *

Proposal: remove summarize and add the totals as options for the count (therefore getting only one leave level with only analyzes).

Start with count_occurrences, summarize_num_patients, and build_table, then read the linked rtables issue 663 for context. Reproduce the example with ex_adae and ex_adsl, focusing on how pruning totals changes the leaf indentation. Done means the proposed handling of totals preserves the intended hierarchy and clearly resolves whether the dcd rows should remain unindented.