[Backport 2.x] bwc test for text chunking processor

[yuye-aws]

Description

Backport PR from https://github.com/opensearch-project/neural-search/pull/661

Issues Resolved

Backport PR from https://github.com/opensearch-project/neural-search/pull/661

Check List

• [x] New functionality includes testing.
  • [x] All tests pass
• [x] New functionality has been documented.
  • [x] New functionality has javadoc added
• [x] Commits are signed as per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[vibrantvarun]

Waiting for this PR on ml-commons to get merged

[yuye-aws]

The ml-commons PR gets merged in main and 2.x branch: https://github.com/opensearch-project/ml-commons/pull/2351