Test suite fails on 8.x-1.x with current Drupal core

Every pipeline on the 8.x-1.x branch fails with the same 3 errors and 1 failure, regardless of what the MR changes — see for example job 10896707 on #3602805: Automated Drupal 12 compatibility fixes for search_api_sorts 1.x-dev. Verified on Drupal 11.4.5 / PHP 8.3.30.

1. SearchApiSortsKernelTest (2 errors): "Could not retrieve data definition for field 'Body' on index 'Test index'". The test installs the config of search_api_test_db, but is missing the module that provides the body field. search_api's own kernel tests install search_api_test_example_content for this exact reason.
2. SearchApiSortsUpdate8102Test (1 error): "Unknown column 'alias' in 'INSERT INTO'" on the {router} table. SearchApiSortsUpdateBase::setUp() rebuilds the routes before the core updates run, but the older drupal-10.3.0.filled.standard.php.gz fixture is missing this column (which was added by system_update_11201).
3. SearchApiSortsUpdate8103Test (1 failure): Expects 'Title', gets 'Titre'. Core only stores English config overrides when locale.settings.translate_english is TRUE. Otherwise, the override is silently dropped, so search_api_sorts_update_8103() never sees it.

Proposed resolution

1. Add field, text, and search_api_test_example_content to the kernel test's modules, and install the example content config before search_api_test_db.
2. Use the drupal-11.3.0.filled.standard.php.gz fixture when core ships it, falling back to 10.3.0.
3. Set locale.settings.translate_english to TRUE in the update test's own database fixture.