fix: allow indexed_shape-only geo/xy shape queries

[arimu1]

Description

Fixes #2011.

GeoShapeQueryField (and the sibling XyShapeQueryField) currently mark shape as required. OpenSearch documents that a geo/xy shape query may use either an inline shape or a pre-indexed shape via indexed_shape (not both). Because the generated builder enforces shape, callers cannot construct valid pre-indexed shape queries:

new Query.Builder()
    .geoShape(g -> g
        .field("location")
        .shape(s -> s.indexedShape(i -> i.index("shapes").id("id").path("location")))
    )
    .build();

Changes

• Remove required: [shape] from _common.query_dsl___GeoShapeQueryField and _common.query_dsl___XyShapeQueryField in java-codegen/opensearch-openapi.yaml
• Update generated GeoShapeQueryField / XyShapeQueryField so shape is @Nullable (no ApiTypeHelper.requireNonNull, conditional serialization, null-safe equals/hashCode)
• Add unit coverage for indexed_shape-only construction/serialization
• CHANGELOG entry under Unreleased 4.x Fixed

Related

• Upstream API-spec discussion: [BUG] shape should not be required in GeoShapeQueryField (blocks pre-indexed shape queries in generated clients) opensearch-api-specification#1160 / Fix copy-paste mistake in NeuralSearch sample #1161 (same schema correction). This client PR unblocks users of the generated DSL until the next full spec refresh.

Testing

./gradlew :java-client:test \
  --tests org.opensearch.client.opensearch._types.query_dsl.GeoShapeQueryFieldTest \
  --tests org.opensearch.client.opensearch._types.query_dsl.XyShapeQueryFieldTest

Temurin 21 / macOS — 4 tests, 0 failures (toBuilder + indexedShapeOnly for both classes).

Check List

• New functionality includes testing
• New functionality has been documented if needed (N/A — aligns client with existing API docs)
• API changes companion issue/PR for opensearch-api-specification (prior attempt Fix copy-paste mistake in NeuralSearch sample #1161)
• Commits are signed per DCO with Signed-off-by

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.