fix: #3624656 Drop the search_api_exclude dependency nothing provides

Issue: https://www.drupal.org/project/varbase_podcasts_base/issues/3624656

config/node.type.podcast.yml declared search_api_exclude in dependencies.module and carried a third_party_settings.search_api_exclude block, but nothing in this recipe's chain requires that module: not the recipe, not varbase_content_base, varbase_media_base, varbase_seo_base or varbase_workflow_base. The only provider in the suite is drupal_cms_search, which reaches a site through varbase_starter, which this recipe does not require.

So a composer require drupal/varbase_podcasts_base plus the four base recipes the README names applies the content type with an unmet module dependency. CI hides it, because CI installs onto a full Varbase Starter site where the module is present for other reasons.

varbase_blog_base and varbase_news_base, which this content type was adapted from, carry neither the dependency nor the settings block, which is what marks it as an export artefact rather than deliberate configuration. Declaring the module instead was weighed and dropped: nothing in the recipe uses the feature.

Also carries logo.png, the 512x512 Varbase drop varbase_blog_base, varbase_news_base and varbase_events_base each ship at the repository root. This was the only base recipe without one.

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