Point cloud dataset doesn't allow no-CRS data

[olsen232]

To Reproduce kart import some-laz-file-that-doesnt-have-a-crs.laz (You can agree to constrain-to-COPC or not - makes no difference.)

Expected behaviour Should import the tiles, even with no CRS.

Output A stacktrace, ending with: RuntimeError: OGR Error: Corrupt data

Version Info kart 0.14 affects all platforms

Also TODO: check if we support GeoTIFF files with no CRS