Add Delta Lake source to the Java Managed API

[chamikaramj]

Github issue #38555.

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[gemini-code-assist]

Summary of Changes

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This pull request introduces support for Delta Lake as a source within the Apache Beam Java Managed API. By implementing a new SchemaTransform provider and updating the Managed API registry, users can now easily integrate Delta Lake tables into their pipelines using a unified configuration interface. The changes include necessary updates to the pipeline model definitions and comprehensive testing to ensure correct functionality.

Highlights

• Delta Lake Integration: Added support for reading from Delta Lake tables via the Java Managed API.
• Schema Transform Provider: Implemented DeltaReadSchemaTransformProvider to enable schema-based transformations for Delta Lake sources.
• Managed API Updates: Registered the new Delta Lake source in the Managed API and updated the pipeline model with the corresponding URN.
• Testing: Added a new integration test case to verify the managed Delta Lake read functionality.

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[gemini-code-assist]

Code Review

This pull request adds support for reading from Delta Lake tables using the Managed API by introducing DeltaReadSchemaTransformProvider, registering the DELTA_LAKE_READ URN, and updating the Managed class. Feedback highlights a compilation issue in DeltaIOTest.java due to missing imports for Files and StandardCharsets, and suggests adding a defensive null check for the configuration in DeltaReadSchemaTransform.

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[chamikaramj]

Thanks!