Load SpikeGLX lf data when meta for ap is not available

[h-mayorquin]

This comes from a discussion with @rly.

Currently, when loading LF, we load the probe from the AP meta:

spikeinterface/src/spikeinterface/extractors/neoextractors/spikeglx.py

Lines 76 to 83 in e45a8be

	if "nidq" not in self.stream_id and not load_sync_channel:
	signals_info_dict = {e["stream_name"]: e for e in self.neo_reader.signals_info_list}
	meta_filename = signals_info_dict[self.stream_id]["meta_file"]
	# Load probe geometry if available
	if "lf" in self.stream_id:
	meta_filename = meta_filename.replace(".lf", ".ap")
	probe = probeinterface.read_spikeglx(meta_filename)

The reason is that the shank map is only available in the AP meta, and that is needed to load the probe:

#596 (comment)

I propose that if the AP meta is not present for any reason, we load the data without the probe so users can at least access it. I think this might prevent loading the inter_sample_shift property?

But maybe with all the new metadata changes in Neuropixels, we can retrieve the probe information and the inter-sample shift in a simpler way.

Thoughts?

[alejoe91]

That's ok on my end!

[h-mayorquin]

@samuelgarcia any thoughts? I can move forward and implement this if there are no obvious downsides. We can improve this in the future once we have better access to the metadata.