Fix quad-base with custom names

[alejoe91]

Update to deal with Quad Base when a custom name is used.

There are 3 different cases:

1. (handled) The custom probe name corresponds to the serial number. In this case, the probe is assigned a name based on the stream name, which already containes the "-{shank_id}" suffix to identify the shank. (e.g. this probe)

2. (handled) The custom probe name DOES NOT correspond to the serial number, but the shank id is part of the name, so the probe is unambiguously selected (e.g., this probe)

3. (handled by this PR) The custom name DOES NOT correspond to the serial number and it DOES NOT have the shank id in its name. In this case (before this PR), multiple probes with the same name were generated, so the wrong probe could have been selected. This PR fixes it by appending the shank id from the probe attribute to the name (e.g., this probe)

The fix is simply this:

# For Quad Base probes, the stream name is the same for all 4 shanks,
# so we append the shank id to match the stream name (if not already present)
# and ensure consistency with stream names.
shank = np_probe.attrib.get("shank")
if shank is not None:
    shank_str = f"-{int(shank) + 1}"
    if shank_str not in name:
        name = f"{name}{shank_str}"
        # update the name in the probe_name_used so that the correct probe name
        # shows up in the list of available probe names
        probe_names_used[probe_idx] = name

Also updated tests to check that the correct shank is loaded using the contact x positions!

[chrishalcrow]

Nice!