Account for bool being passed.
Previous iteration of calendar_links twig method allowed/required boolean as fourth parameter.
If bool is not changed to a string in calendar_links, get_class() will receive a boolean and errror out.
This still doesn’t account for the possibility of a number.
This is also very opinionated, I’m not sure what other methods may be using getString- so perhaps that message is terribad.
Obviously, change however you see fit.
Closes #3284487