Update `TermsAggregation`, `CardinalityExecutionMode` fields

[karenyrx]

Description

1. TermsAggregation: Removed unsupported fields

Removed missing_order and missing_bucket fields from TermsAggregation as they are not supported by TermsAggregationBuilder.

• Evidence: TermsAggregationBuilder.PARSER (lines 119-159) does not parse missing_order or missing_bucket fields
• Evidence: TermsAggregationBuilder.doXContentBody() (lines 353-404) does not serialize these fields
• These fields belong to CompositeAggregation and were incorrectly included in the TermsAggregation spec

Source references:

• TermsAggregationBuilder.java#L119-L159 - Parser definition
• TermsAggregationBuilder.java#L353-L404 - Serialization

2. TermsAggregation: Added missing shard_min_doc_count field

Added the shard_min_doc_count field which is supported by TermsAggregationBuilder.PARSER but was missing from the spec

3. CardinalityExecutionMode: Added segment_ordinals enum value

Added segment_ordinals execution hint option introduced in OpenSearch 2.19.1 via PR #17312.

• Evidence: CardinalityAggregationBuilder#executionHint() method added in 2.19.1

Source references:

• PR #17312 - Introduce execution_hint for Cardinality aggregation
• Commit 968eafb - Add execution_hint support

Issues Resolved

Part of https://github.com/opensearch-project/opensearch-protobufs/issues/30

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.

[github-actions[bot]]

Changes Analysis

Commit SHA: 1e400eaa5292eef563c8d0aa9d933a7d2db5c8fb Comparing To SHA: 8978c523e39389afa894ea3cc6fe7a19c624985e

API Changes

Summary

└─┬Components
  ├─┬_common.aggregations___TermsAggregation
  │ └─┬ALLOF
  │   ├──[➖] properties (43893:13)❌ 
  │   ├──[➖] properties (43891:13)❌ 
  │   └──[➕] properties (43905:13)
  └─┬_common.aggregations___CardinalityExecutionMode
    └──[➕] enum (41648:11)

Document Element	Total Changes	Breaking Changes
components	4	4

• ❌ BREAKING Changes: 4 out of 4
• Removals: 2
• Additions: 2
• Breaking Removals: 2

Report

The full API changes report is available at: https://github.com/opensearch-project/opensearch-api-specification/actions/runs/19878183105/artifacts/4745024278

API Coverage

	Before	After	Δ
Covered (%)	666 (65.23 %)	666 (65.23 %)	0 (0 %)
Uncovered (%)	355 (34.77 %)	355 (34.77 %)	0 (0 %)
Unknown	129	129	0

[github-actions[bot]]

Spec Test Coverage Analysis

Total	Tested
682	680 (99.71 %)