Make sec10k assets work with integration tests

[zaneselvans]

• The sec10k tables are only loaded when the USE_PUDL_MODELS environment variable is set.
• Currently it is not set in the pytest workflow in our CI, so the sec10k assets aren't tested by our integration tests when a PR gets put in the merge queue.
• If USE_PUDL_MODELS is set in our CI, the runner doesn't have permission to pull the sec10k assets, so the tests fail.
• Because there are utility_id_eia values from a wide range of years in the out_sec10k__ tables, and all of them are loaded any time the asset is loaded, in the etl_fast integration tests, there are FK constraint violations -- since only a few years of EIA-860 data is present in the database.
• This means that if you have USE_PUDL_MODELS set locally, you cannot get make pytest-integration to pass, and pytest-integration only passes in CI because the sec10k assets aren't being tested.
• How should we ensure that these assets get tested and are able to pass the integration tests both locally and in CI?