I was able to get this container to work based on @ufo56 comment that the config files aren't used anymore. I removed those from the container variables and only have the following.
Identify the USB port and device ID on your unRAID server from the command prompt with the lsusb command:
# lsusb
Bus 002 Device 004: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
Variables:
RTL-SDR Device: /dev/bus/usb/002/004:/dev/bus/usb/002/004
HTTP Port: <blank>
FR24FEED_FR24KEY: <own key>
PANORAMA_ID: <optional>
HTML_SITE_LAT: <required>
HTML_SITE_LON: <required>
SERVICE_ENABLE_PIAWARE: false
HTML_DEFAULT_TRACKER: Flightradar24
HTML_SITE_NAME: MySite
HTML_RECEIVER_STATS_PAGE_FLIGHTRADAR24: <optional>
LAYERS_OWM_API_KEY: <optional>