Ignore missing package in `SCRIPT_START` callback

[squili]

Somehow, a repo I made started getting this error during installation, but the installation itself went fine. Given that it's only used for updating the progress display, and if we don't know about it we're probably not displaying it's progress, it should be fine to ignore.

[pep8speaks]

Hello @squili! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers:

Comment last updated at 2022-08-10 02:52:35 UTC

[m-blaha]

Thanks for the pull request! I'm afraid that this PR only hides the symptom. I'm really curious what the root cause of the issue might be. Are you able to reproduce the issue consistently? Do you remember what have you done with your repo to start getting this message? If it is unclear how to prepare such failing repo, is it possible to share your current one to reproduce the issue?

[squili]

We have a large rollout very soon of a repo that reliably produces this result, so I didn't have time to debug too far deep. You can find the repo itself at https://pkg.fig.io/yum/f36/x86_64/repodata/repomd.xml I know it's missing a lot of fields, but we don't have time to set up the standard repository creation system - and anyways, this error should probably not be happening at an otherwise functioning repository