[S] Add unit to total attendance for Day Use activities

## Description
As a bc parks admin A&R user, I want to easily understand what the total field on Day Use Activity means.

This is a display update only, no change to calculation.

`Day Use Activity` form would show:
1. Total Attendance (People), (Vehicle count x 3.5) = (Bus count x 40) + trail count

## Acceptance Criteria
- Field in A&R admin UI shows `Total Attendance (People)` on day use activity instead of `Day Use (attendance)`

## Notes