text: Title: db clean and search-index rebuild should remove orphans from index
  Body: ## CKAN version
  all
  
  ## Describe the bug
  Old copies of metadata in the solr search index can cause performance and search result issues
  
  ### Steps to reproduce
  - create a dataset on a clean db
  - run `ckan db clean`
  - create a dataset with the same name
  - search now returns both datasets, and package_show with `id=name` is very slow
  
  ### Expected behavior
  Only the latest dataset is visible in search and retrieving datasets will act normally
  
  ### Additional details
  `ckan search-index clear`, `ckan search-index rebuild -c` or a later call to `ckan search-index clear-orphans` will fix the issue, but it would be nicer for `db clean` to clear the search index, and `search-index rebuild` should `clear-orphans` by default.
  
  reference: #7044
  
  