Update listExtensions.m

[ehennestad]

Motivation

Add filter to ignore extensions without a name when retrieving metadata for all published ndx-extensions.

Background:
An empty repository was created for a staged extension in the nwb-extensions organization. This added the following entry to the nwb-extension records:

{
    "ndx_fscv_record": {
        "ref": "ndx-fscv-record",
        "record_url": "https://github.com/nwb-extensions/ndx-fscv-record",
        "last_updated": "2026-01-07T16:55:57Z"
     }
}

This repository uses that records file to create a list of extensions, but the code failed when an extension without required metadata is present. This PR fixes that by ignoring entries in the records file which does not have a name.

How to test the behavior?

Running this command should work

matnwb.extension.listExtensions()

Currently (2026-01-13) this command fails on main due to the state of the ndx-extensions organization.

Checklist

• Have you ensured the PR description clearly describes the problem and solutions?
• Have you checked to ensure that there aren't other open or previously closed Pull Requests for the same change?
• If this PR fixes an issue, is the first line of the PR description fix #XX where XX is the issue number?