Added in #17912, was a bad copy and paste.

Co-authored-by: Olivier 'reivilibre <oliverw@matrix.org>

This was due to a missing index, which meant that deleting previous
connections associated with the device and `conn_id` took a long time.

To work around the fact that,
pre-https://github.com/element-hq/synapse/pull/17903, our database may
have old one-time-keys that the clients have long thrown away the
private keys for, we want to delete OTKs that look like they came from
libolm.

To spread the load a bit, without holding up other background database
updates, we use a scheduled task to do the work.

Fixes: https://github.com/element-hq/element-meta/issues/2155
Fixes: https://github.com/element-hq/synapse/issues/2046

### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [X] Pull request is based on the develop branch
* [X] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [X] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

MacOS 12 is end-of-life and GitHub is deprecating support for it
(including doing brown outs). Let's bump to MacOS 13.

We were pinned to an old version that had deprecation warnings.

In new versions of the action leaving off properties (i.e. `draft` and
`prerelease`) tells the action to not modify those properties of the
release.

Broke in #17905 due to upgrading the `upload-artifact` action, as we
didn't rename debs. I think we also need to change how we download the
artefacts and attach them to a release, as they'll download to a
different place.

Docs:
- https://github.com/actions/upload-artifact/tree/v4/
- https://github.com/actions/download-artifact/tree/v4/

As we're now using it in the sync APIs to get state changes within a
room

Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>