Migrate datanode upgrade service adapter

[todvora]

/nocl internal migration to os3 client

Description

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (non-breaking change)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have requested a documentation update.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[Copilot]

Pull request overview

Migrates the datanode upgrade service adapter to use the OpenSearch 3 client and aligns shard replication/flush operations with the new adapter contract and typed health status.

Changes:

• Updates DatanodeUpgradeServiceAdapter to return FlushResponse from shard replication operations and removes the standalone flush() method.
• Switches cluster health from String to typed HealthStatus across DTOs/services and updates comparisons accordingly.
• Introduces new adapter implementation/tests for OpenSearch 3 and adds/adjusts integration tests for OpenSearch 2/3.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
graylog2-server/src/test/java/org/graylog2/datanode/DatanodeUpgradeServiceTest.java	Adjusts tests to use typed HealthStatus and new adapter method signatures.
graylog2-server/src/test/java/org/graylog/plugins/datanode/DatanodeUpgradeServiceAdapterIT.java	Adds shared integration test coverage for adapter upgrade operations.
graylog2-server/src/main/java/org/graylog2/indexer/indices/HealthStatus.java	Adds uppercase toString() to align string representation with external expectations.
graylog2-server/src/main/java/org/graylog2/datanode/DatanodeUpgradeService.java	Updates health checks and replication start/stop to match adapter contract changes.
graylog2-server/src/main/java/org/graylog/plugins/datanode/dto/ClusterState.java	Changes status type from String to HealthStatus.
graylog2-server/src/main/java/org/graylog/plugins/datanode/DatanodeUpgradeServiceAdapter.java	Changes adapter API: shard replication methods return FlushResponse, removes flush().
graylog-storage-opensearch3/src/test/java/org/graylog/storage/opensearch3/DatanodeUpgradeServiceAdapterOSIT.java	Adds OS3-specific integration test wiring for the new adapter.
graylog-storage-opensearch3/src/main/java/org/graylog/storage/opensearch3/OpenSearch3Module.java	Binds the supported adapter to the new OS3 implementation.
graylog-storage-opensearch3/src/main/java/org/graylog/storage/opensearch3/DatanodeUpgradeServiceAdapterOS2.java	Removes the OS2-based adapter from the OS3 module.
graylog-storage-opensearch3/src/main/java/org/graylog/storage/opensearch3/DatanodeUpgradeServiceAdapterOS.java	Adds new OS3 adapter using the official OpenSearch Java client.
graylog-storage-opensearch2/src/test/java/org/graylog/storage/opensearch2/DatanodeUpgradeServiceAdapterOS2IT.java	Adds OS2 integration test wiring based on the shared adapter IT.
graylog-storage-opensearch2/src/main/java/org/graylog/storage/opensearch2/DatanodeUpgradeServiceAdapterOS2.java	Updates OS2 adapter to typed HealthStatus and new replication/flush contract.
graylog-storage-elasticsearch7/src/main/java/org/graylog/storage/elasticsearch7/DatanodeUpgradeServiceAdapterES7.java	Updates ES7 adapter to the new FlushResponse-returning method signatures.

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[Copilot]

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 6 comments.

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