Remove `read_sf() format =kml` from `bcdc_read_functions()`

[stephhazlitt]

From the B.C. Data Catalogue team:

As of June 28th, 2023, KML files will now serve data in image/png format instead of application/kml. This change improves service reliability and responsiveness.

Seems like we can remove

bcdata/R/get_data.R

Line 264 in b9913f9

"kml", "sf", "read_sf",

.