feat(grpc): Add gRPC vector bulk ingestion with extra_field_values

[finnegancarroll]

Description

Add support for bulk indexing vectors over gRPC using the extra_field_values optimization from OpenSearch PR #20635. Vectors are sent as packed little-endian binary (FloatBinaryLE) via the protobuf extra_field_values side-channel, bypassing JSON serialization entirely.

• Add build_proto_vector_request() to ProtoBulkHelper for building BulkRequest with FloatBinaryLE encoding in extra_field_values map
• Add ProtoBulkVectorsFromDataSetParamSource that reads HDF5 vectors as numpy arrays and passes them as binary (no .tolist() conversion)
• Add ProtoBulkVectorDataSet runner and OperationType (204)
• Bump opensearch-protobufs dependency from ==1.2.0 to >=1.4.0
• Add 7 unit tests covering protobuf message construction and param source behavior

Issues Resolved

N/A

Testing

• New functionality includes testing

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AI-powered 'Code-Diff-Analyzer' found issues on commit a5323d8.

Path	Line	Severity	Description
setup.py	134	high	Dependency version constraint for 'opensearch-protobufs' changed from a pinned version (==1.2.0) to an open-ended range (>=1.4.0). This allows any future version to be resolved at install time, which could introduce unvetted or malicious releases. Maintainers should verify the package integrity for all versions in the allowed range and consider using a more restrictive constraint (e.g., >=1.4.0,<2.0.0).

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