Refactor for loops to use purrr in mapvizier_summary.R

[almartin82]

Summary

• Replace imperative for loops with purrr::pmap_int() for calculating cohort status NPRs
• Applies to both summary.mapvizieR_growth and summary.mapvizieR_cdf functions
• Add purrr (>= 1.0.0) as package dependency

Changes

Before (imperative):

for (i in seq_len(nrow(mapSummary))) {
  mapSummary[i, ]$start_cohort_status_npr <- cohort_mean_rit_to_npr(...)
  mapSummary[i, ]$end_cohort_status_npr <- cohort_mean_rit_to_npr(...)
}

After (functional):

mapSummary <- mapSummary %>%
  dplyr::mutate(
    start_cohort_status_npr = purrr::pmap_int(
      list(measurementscale, start_grade, start_fallwinterspring, start_mean_testritscore),
      cohort_mean_rit_to_npr
    ),
    end_cohort_status_npr = purrr::pmap_int(
      list(measurementscale, end_grade, end_fallwinterspring, end_mean_testritscore),
      cohort_mean_rit_to_npr
    )
  )

Test plan

• All 997 tests pass
• summary.mapvizieR_growth produces same output
• summary.mapvizieR_cdf produces same output

Fixes #314