Weekly data should require week numbers

```
states <- "ca,fl,ny,tx"
today <- 20240730
pub_covidcast(
  source = "nssp",
  signals = "pct_ed_visits_covid",
  time_type = "week",
  geo_type = "state",
  time_values = epirange(20221001, today),
  geo_values = states,
  issues = epirange(20000101,today)
)
```
it isn't immediately clear why this returns no data, for example