handle adding fires with no stations better.

When trying to add a fire that does not have stations, this error comes up.

poetry run flowalert debrisflow add fal2024
INFO:root:Downloading shapefiles url https://landslides.usgs.gov/static/landslides-realtime/fires/fal2024/Shapefiles.zip
'STATION'

The user then has to run config delete on the fire, and manually delete the downloaded debrisflow directory

Acceptable criteria

• confirm this error is coming from no stations existing within fire perimeter
• Error message is more descriptive. Should say something like fire fal2024 does not have any stations within {buffer_m} of the fire perimeter
• Fire is automatically deleted from config.ini file.
• Debrisflow directory is automatically deleted.