setting tolerance instead of max in delay options doesn't work

[sbfnk]

Summary:
The delay_opts() family of functions sets a default tolerance and thus should work without setting a maximum. Currently, however, doing so results in an error.

Reproducible Steps:

library("EpiNow2")
#> 
#> Attaching package: 'EpiNow2'
#> The following object is masked from 'package:stats':
#> 
#>     Gamma
generation_time_opts(Gamma(mean = 3.6, sd = 3.1))
#> Error in check_stan_delay(dist): All distribution passed to the model need to have a finite maximum

^{Created on 2024-05-09 with reprex v2.1.0}

Related: #533