More useful error message if enable_load_extension is not available #1979
Description
I get this from:
datasette --load-extension spatialite --get /-/versions.json
File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/datasette/app.py", line 614, in _prepare_connection
conn.enable_load_extension(True)
AttributeError: 'sqlite3.Connection' object has no attribute 'enable_load_extension'
It would be useful if Datasette caught this error and output something more friendly.