Elasticsearch: update_document irrelevant

Summary

We override update_document method. However in the normal circumstances it is bypassed, and ultimately triggers index_document instead.

This is because we trigger indexing asynchronously, but update_document would only do a proper update operation when the attribute changes are stored in the @__changed_model_attributes instance variable (this is setup by elasticsearch-rails' before_save callback).

Note indexing would still be done properly, because as passing the whole document to elasticsearch for indexing is perfectly valid.

We can either:

• Update its only caller IndexRecordService to always call index_document instead.
• Pass changed attributes when asynchronously schedule indexing

Improvements

Remove unused code so is easier to understand.

Risks

N/A