* fix delete empty tags query
* rewrite as a single statement
* create tag service medium test
* single tag exists, connected to one asset, and is not deleted
* do not delete parent tag if children have an asset
* hierarchical tag tests
* fix query to match 3 test
* remove transaction and format:fix
* remove transaction and format:fix
* simplify query, handle nested empty tag
* unused helper
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Co-authored-by: mertalev <101130780+mertalev@users.noreply.github.com>