[DOC] Remove compatibility override from breaking changes

[arvindmahesh]

What do you want to do?

• Request a change to existing documentation
• Report a technical problem with the documentation

Tell us about your request. Provide a summary of the request and all versions that are affected.

https://opensearch.org/docs/2.0/breaking-changes/

We list "Deprecate Compatibility override" as one of the breaking changes. We had originally made that change, but reverted it.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

Github issue for the revert: opensearch-project/OpenSearch#3023 (comment)