perf: small reduction of DB queries

[jrief]

Description

This PR reduces the number of DB queries by a few.

Related resources

1. chunk: fallback languages can be cached inside the Page object.
2. chunk: Replacing the .filter(…) on the queryset against .all() actually reduces the number of queries. This is because that queryset in most cases is already consumed. Calling it with .filter(…) actually fetches the data a second time. Therefore filtering in Python is cheaper, especially if the number of languages never exceeds a significant number.

Also read https://docs.djangoproject.com/en/5.0/ref/models/querysets/#values

Checklist

• I have opened this pull request against develop-4
• I have added or modified the tests when changing logic
• I have followed the conventional commits guidelines to add meaningful information into the changelog
• I have read the contribution guidelines and I have joined #workgroup-pr-review on Slack to find a “pr review buddy” who is going to review my pull request.

[fsbraun]

I like the all() optimisation.

How does caching the fallback languages help performance. The fallback languages only depend on the settings, or am I missing something?

[vinitkumar]

@jrief Are there any updates on this? Also, would be great to see the number of queries reduction shown by Django Debug Tool or something? In my opinion, it would be help remember the rationale behind the change in future.