ai_search module is missing search_api as a dependency

It is as expected that it should prevent install until you composer require the Search API module. It is in require-dev so automated tests run but it is not a dependency of the AI module where the composer.json sits. Composer.json does not work in sub directories so we cannot put it as a require for the sub-module only unfortunately. A downside of using sub-modules but we believe the benefit of joining together efforts of what was previously a fairly fragmented community of AI related modules is worth these downsides.