Fix: stale term-search cleanup before reindexing

[mdorf]

Description

Fixes ncbo/ontologies_api#227.

NPDX suggest/autocomplete search was returning stale capitalized classes from an older ontology submission. Selecting those results led to 404s because the class records were no longer present in the latest NPDX submission.

The term indexer was calling the generic Ontology#unindex path before indexing new terms. For ontology records, that path does not perform acronym-scoped class term cleanup, so stale class documents from older submissions could remain in Solr term_search and appear in suggest=true search results.

Changes

• Use unindex_by_acronym(false) before term reindexing so existing class docs for the ontology acronym are removed from term_search.
• Use unindex_all_data(index_commit) when deleting ontology submissions so term and property index cleanup go through the explicit cleanup path.
• Add a regression test confirming term indexing clears existing term docs by acronym before continuing.

Verification

bundle exec rake test TEST="./test/models/test_ontology_submission.rb" TESTOPTS="--verbose --name=test_index_terms_clears_existing_term_docs_by_acronym"