[kemono] KeyError - 'name'

[TestPolygon]

It fails on some subscribestar posts.

kemonoparty][debug]
Traceback (most recent call last):
  File "C:\Users\Username\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\job.py", line 76, in run
    for msg in extractor:
  File "C:\Users\Username\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\extractor\kemonoparty.py", line 103, in items
    text.nameext_from_url(file["name"], post)
KeyError: 'name'

It looks it happens when the old formatted URL is used.

    "file": {
      "path": "/attachments/subscribestar/username/12345/filename.png"
    },