Improve argument checks

[olivroy]

Use rlang type checks

https://github.com/tidyverse/ggplot2/pull/5209/files

Remove dependency on asserthat.

https://usethis.r-lib.org/reference/use_standalone.html

[rolkra]

Great Work!
Just one thing that I recognised: fct_na_value_to_level() seems to add a new dependency to forcats 1.0.0 as this function seems to be introduced in 1.0.0. So this should be added to DESCRIPTION

[olivroy]

@rolkra indeed, do you want me to add this to this PR?

Edit, did this in bf62ff0