Return of Fix first time prod editor-api project builds

[adrian-rpf]

Previously, this issue was investigated and thought to be resolved by #257

This is being reopened as it appears that the issue still exists: https://raspberrypifoundation.slack.com/archives/C02JBAA2NFP/p1738748427420069

[create-issue-branch]

Branch bugfix/487-Return_of_Fix_first_time_prod_editor-api_project_builds created!

[danhalson]

Whilst no single issue has been identified to explain this, a number of smaller ones have been created or raised as a result of this. I think we should close the issue now and raise another one if needed as hopefully with the improvements listed below, the issue has been improved, if not resolved.

Some errors weren't being surfaced correctly owing to how GraphQL (used for querying the Github API) returns errors, this has been fixed now: #503

Some jobs may have been failing due to transient issues, to mitigate this there are now retries on the UploadJob, so that it tries three times before giving up and raising an error: #506

Private repos weren't accessible by the bot account used to run the Webhook on Github, this has been changed by elevating the permissions of this account, and they can now access all repos, although with limited permissions. This could account for the first time build failures, since new repos are private by default and would have been changed to public later. This will no longer be an issue, but time will tell if this improves things: #505

Most importantly we need to ensure that the Educator team have good visibility of the status of builds once the webhook has fired, currently an update is sent to the #product-notifications channel in Slack, and then no further updates are sent. They are able to access the Good Job dashboard to check progress, however, many of them aren't aware of this and it's not very user friendly. We need to implement Slack Notifications as we have on projects-admin and the lambdas, an issue has been raised here: #505

An additional issue identified during the process is that the Educator team aren't all aware of our documentation, and it may be we need to make improvements to this too: https://github.com/RaspberryPiFoundation/digital-editor-issues/issues/450