Fixing splat masking and double distortion

[AntonioMacaronio]

for aria, there is a runtime error when boolean masks are fed into splatfacto:

Additionally, when the distortion parameters are all 0 (meaning there is no distortion in the image), splatfacto will still try to distort the image because distortion_params are not None, so adding a quick check on that prevents images from being fed to the undistort function when there is no distortion.