There can be more than one network location for an instance ID

[bjester]

Summary

• Fixes issue where filtering by instance_id could encounter an error if there are multiple NetworkLocations with the same ID, which I forgot about when I wrote the original code

References

In logs from @marcellamaki

ERROR 2023-11-17 12:01:17,019 kolibri.core.content.utils.content_request get() returned more than one NetworkLocation -- it returned 2!
Traceback (most recent call last):
  File "/Users/marcellamaki/Documents/learning-equality/kolibri/kolibri/core/content/utils/content_request.py", line 769, in process_download_request
    for peer in chain(*peer_sets):
  File "/Users/marcellamaki/Documents/learning-equality/kolibri/kolibri/core/content/utils/content_request.py", line 286, in __iter__
    peer = self._get_and_validate_peer(instance_id)
  File "/Users/marcellamaki/Documents/learning-equality/kolibri/kolibri/core/content/utils/content_request.py", line 250, in _get_and_validate_peer
    peer = NetworkLocation.objects.get(
  File "/Users/marcellamaki/.pyenv/versions/3.9.9/envs/kolibri-develop/lib/python3.9/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/marcellamaki/.pyenv/versions/3.9.9/envs/kolibri-develop/lib/python3.9/site-packages/django/db/models/query.py", line 382, in get
    raise self.model.MultipleObjectsReturned(
kolibri.core.discovery.models.MultipleObjectsReturned: get() returned more than one NetworkLocation -- it returned 2!

Reviewer guidance

I wrote a regression test for it, which failed, then fixed the issue and the test passed, as well as all others.

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[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.16.0b8.dev0_git.41.ga780bf79.pex
Windows Installer (EXE)	kolibri-0.16.0b8.dev0+git.41.ga780bf79-unsigned.exe
Debian Package	kolibri_0.16.0b8.dev0+git.41.ga780bf79-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.0b8.dev0+git.41.ga780bf79-0.3.0.dmg
Android Package (APK)	kolibri-0.16.0b8.dev0+git.41.ga780bf79-0.1.0-debug.apk
TAR file	kolibri-0.16.0b8.dev0+git.41.ga780bf79.tar.gz
WHL file	kolibri-0.16.0b8.dev0+git.41.ga780bf79-py2.py3-none-any.whl