Shorter logging for mirrorer upload failures

[HebaruSan]

Problem

The Discord channel is being spammed with long upload errors along these lines:

  File "/home/netkan/.local/lib/python3.12/site-packages/netkan/mirrorer.py", line 297, in process_queue
    if self.try_mirror(CkanMirror(self.ia_collection, path)):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/netkan/.local/lib/python3.12/site-packages/netkan/mirrorer.py", line 322, in try_mirror
    item.upload_file(download_file.name, ckan.mirror_filename(),
  File "/home/netkan/.local/lib/python3.12/site-packages/internetarchive/item.py", line 1131, in upload_file
    raise type(exc)(error_msg, response=exc.response, request=exc.request)
requests.exceptions.HTTPError:  error uploading AB0139C2-ChineseModPatches-v1.4.1.zip to ChineseModPatches-v1.4.1, The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. For more information, see REST Authentication and SOAP Authentication for details.

Cause

An exception is being thrown during the attempt to upload to archive.org and logged in full. Most of the output is a useless stack trace into library code that we don't care about.

Changes

Now we log a simple short message and move on.