[DOC] Remove aggregation and concurrent segment search from limitations of derived fields

[rishabhmaurya]

What do you want to do?

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

Tell us about your request. Provide a summary of the request.
Aggregations and Concurrent segment search, which are currently set as limitation, will be supported from 2.17 and onwards.
Aggregation support is fixed by opensearch-project/OpenSearch#14618 thanks @mch2
Derived fields support is fixed by opensearch-project/OpenSearch#15072 thanks @jed326

There is an open issue #7850 to add derived field aggregation examples in the documentation as well.

*Version: List the OpenSearch version to which this issue applies, e.g. 2.14, 2.12--2.14, or all.
2.17

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

[mch2]

@rishabhmaurya We don't have compatibility with concurrent search yet. In opensearch-project/OpenSearch#15072 @jed326 added some ITs that are currently skipped with concurrent search and fail when executed.

[Naarcha-AWS]

@rishabhmaurya or @mch2: Is there a PR in progress for this?

[mch2]

@Naarcha-AWS will get that up today thanks for the reminder

[mch2]

@Naarcha-AWS Just raised #8222