Run API and Ingestion Server tests with all relevant ES versions

[sarayourfriend]

Fixes

Based on #2777 and related to the comment here: #2777 (review)

Description

Because production is currently stuck on ES 7 until we've figured out why ES 8 caused the queries to take so long, we need to test all our code against both ES versions. Until we've fully transitioned to ES 8 we need to support both versions.

Testing Instructions

Check the new CI tasks and confirm they've run as expected. Locally, run OPENVERSE_ES_VER=7 just api/test locally to test as an example that the environment variable works as expected.

Checklist

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• [N/A] I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no visible errors.
• [N/A] I ran the DAG documentation generator (if applicable).

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[sarayourfriend]

This will also need the required checks changed in the infra repo with the new names. I'll push a commit with changes to ingestion and api so that those steps actually run.

[sarayourfriend]

The most recent CI run confirms that this runs (and that the changes in #2777 should be okay (I think):

https://github.com/WordPress/openverse/actions/runs/5862236561/job/15893876650?pr=2832#step:5:19

Notice that it pulls ES version 7. And here it pulls version 8:

https://github.com/WordPress/openverse/actions/runs/5862236561/job/15893876557?pr=2832#step:5:19

[obulat]

The CI runs prove that this is working.
I've asked inline, too, but do we really need changes to the steps that just "imitate" a CI step, both for the ingestion and the API (the ones that just echo something and don't do anything)?

[obulat]

Do we really need to update this step since it's not really doing anything? It's just the "Pass" step.