pylib spams stack traces on stdout

[davidsauerwein]

The anki pylib logs directly to stdout via print(). A lot of the logs don't seem very interesting to user's of the library. They mostly appear to be debug logs. The most noisy that I have observed very frequently (almost 100% of the time) is the following:

blocked main thread for 424ms:
  File "/home/david/coding_stuff/anki/repro.py", line 4, in <module>
    auth = col.sync_login(
  File "/home/david/coding_stuff/anki/.venv/lib/python3.14/site-packages/anki/collection.py", line 1142, in sync_login
    return self._backend.sync_login(
  File "/home/david/coding_stuff/anki/.venv/lib/python3.14/site-packages/anki/_backend_generated.py", line 83, in sync_login
    raw_bytes = self._run_command(1, 3, message.SerializeToString())
  File "/home/david/coding_stuff/anki/.venv/lib/python3.14/site-packages/anki/_backend.py", line 167, in _run_command
    print("".join(traceback.format_stack()))

It can be reproduced with the following snippet

from anki.collection import Collection

col = Collection("collection.anki2")
auth = col.sync_login(
    username=r"<username>",
    password=r"<password>",
    endpoint="https://sync.ankiweb.net/",
)
col.close()

I already have a fix locally. I'll post a PR shortly.