Small fixes to the daily runs

What does this merge request do and why?

This MR addresses a few tiny problems in the daily run pipelines:

• Update the image pull policy for the daily run job, so that it has the latest changes without the need to recreate the whole pipeline
• Add a new code explanation config without the slash-explain until we have a solution to the request limit
• Update the docs to have the DAILY_RUN_SCHEDULED variable
• Add inference configs and replace foundation models with precomputed answers (the inference results are already in BQ)

Relates to #203

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Merge request checklist

• I've ran the affected pipeline(s) to validate that nothing is broken.
• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.