Error Messages Still Reference Elasticsearch

I came across a Reddit post where a user was having issues with their Graylog install. They are using 6.2.2 which runs Opensearch. A screenshot of the Datanode indexing errors uses "Elasticsearch" to describe the indexing service as opposed to "Opensearch"


You can see in the image above that the strings haven't been changes to the correct indexing service.

I suggest making all reference to the indexing service a constant that is read from a configuration file so that once all instance of the indexing service have been replaced with that constant, you won't ever have to do a search and replace in the code. If a different indexing solution is used in the future, its changed in one place.