Ignore deprecations in search_api

Problem/Motivation

PHPUnit tests at Next Minor 11.3-dev are now producing the following four new deprecations:

/builds/project/gitlab_templates_downstream/web/core/lib/Drupal/Core/Test/HttpClientMiddleware/TestHttpClientMiddleware.php:52
    Providing template_preprocess_search_api_admin_fields_table() is deprecated in drupal:11.3.0 and is removed from drupal:12.0.0. Use initial preprocess for template_preprocess instead. See https://www.drupal.org/node/3504125
    
/builds/project/gitlab_templates_downstream/web/core/lib/Drupal/Core/Test/HttpClientMiddleware/TestHttpClientMiddleware.php:52
    Providing template_preprocess_search_api_admin_data_type_table() is deprecated in drupal:11.3.0 and is removed from drupal:12.0.0. Use initial preprocess for template_preprocess instead. See https://www.drupal.org/node/3504125
        
/builds/project/gitlab_templates_downstream/web/core/lib/Drupal/Core/Test/HttpClientMiddleware/TestHttpClientMiddleware.php:52
    Providing template_preprocess_search_api_server() is deprecated in drupal:11.3.0 and is removed from drupal:12.0.0. Use initial preprocess for template_preprocess instead. See https://www.drupal.org/node/3504125
    
/builds/project/gitlab_templates_downstream/web/core/lib/Drupal/Core/Test/HttpClientMiddleware/TestHttpClientMiddleware.php:52
    Providing template_preprocess_search_api_index() is deprecated in drupal:11.3.0 and is removed from drupal:12.0.0. Use initial preprocess for template_preprocess instead. See https://www.drupal.org/node/3504125

Change record https://www.drupal.org/node/3504125 →

Steps to reproduce

Example https://git.drupalcode.org/project/gitlab_templates_downstream/-/jobs/69...

Proposed resolution

Add patterns for these into .deprecation-ignore.txt