CRS should not be defaulted to LatLng

Describe the bug

For an image without a Spatial Reference system, the default proj4string value of LatLng is being set.

To Reproduce

Provide as able:

• Steps to reproduce the behavior:
  Ingest a GeoTiff that doesn't have a Spatial Reference System.

• Code example:
  val geoTiffRasterSource: GeoTiffRasterSource = GeoTiffRasterSource(geotiffPath)
  val crs: CRS = geoTiffRasterSource.crs

• Inputs

https://drive.google.com/file/d/1P9HPB9uOP3-b48DwBcZ1CIT5UtdYdj-9/view?usp=sharing

• Actual output
  crs = LatLng

• Expected output
  crs = None

Expected behavior

Instead of a default value LatLng, None value should be assigned to CRS.

Environment

• Java version: 1.8.0_265
• Scala version: 2.12.10
• GeoTrellis version: 3.5.0

Additional context

If this is not possible, is there any way I could get the actual Proj4String of the image before assigning the CRS value(LatLng) to the image?

Start at the GeoTiffRasterSource.crs entry point and reproduce the behavior with the linked GeoTiff, checking how a missing Spatial Reference System becomes LatLng. Done means an image without a Spatial Reference System reports CRS as None rather than LatLng; verify the result with the Scala code example.