Use primarycensored's new dependencies argument for Stan function loading

[seabbs-bot]

Summary

primarycensored now has a dependencies argument in pcd_load_stan_functions() that automatically resolves and includes all functions that the requested functions depend on.

See: epinowcast/primarycensored#171

Current state

In #426 there was a need to get a primarycensored Stan function and all its dependencies.

New capability

With the new dependencies = TRUE argument:

pcd_load_stan_functions("primarycensored_lpmf", dependencies = TRUE)

This will automatically include all required functions in the correct order.

There is also a new pcd_stan_function_deps() function to query the dependency graph:

pcd_stan_function_deps("primarycensored_lpmf")

Action

Update epidist to use this new functionality once primarycensored is released with these changes.

[seabbs]

I'm not sure we need this but it could be useful to speed up compile times.