Fix junk data in issues index

Summary

There are multiple data problems in the issues index:

1. Documents with _id like issue_140042675 - causing duplicate documents
2. Documents with schema_version 2312 when the current version is 2405
3. Documents with type work_item
4. Disparity between number of unique IDs and total number of docs

Attempted fixes:

• Added checks in ee/lib/search/elastic/references/work_item.rb and ee/app/models/concerns/search/elastic/issues_search.rb to stop indexing workitems
• ReindexAllIssues to add all documents from the database.
  • First run 2024-01-02T21:06:31
  • Second run 2024-01-05T07:26:08
• RemoveIssueDocumentsBasedOnSchemaVersion to remove docs with schema version < 2312
• RemoveWorkItemFromIssuesIndex to remove all documents with type=workitem and schema version < 2312

Suggested fix:

• Migration to remove all docs with type=work_item from the index
• Bump schema version to 2407
• Migration to reindex all issues from the database - every Issue.without_issue_type(:epic) record is tracked and will have schema version 2407
• Migration to remove docs with schema version < 2407 from index