[Spark] Shade the build for Delta Connect projects

[longvu-db]

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Which Delta project/connector is this regarding?

• [ ] Spark
• [ ] Standalone
• [ ] Flink
• [ ] Kernel
• [ ] Other (fill in here)

Description

Shade the build of connectServer, connectClient and connectCommon projects, this is to avoid conflicts on libraries that Delta Connect library users and the Delta Connect library itself may both depend on such as protobuf, grpc,...

This is needed so that we can ship the Delta Connect project once it is finished.

We hope that this also remove the need of include com.google.protobuf:protobuf-java:3.25.1 in the --packages to use Delta Connect server and client.

https://docs.delta.io/latest/delta-spark-connect.html#how-to-start-the-spark-server-with-delta

How was this patch tested?

Run sbt assembly on the project connectServer, connectClient and connectCommon, and use the jar tf command to manually inspect the content of the jar files.

Does this PR introduce any user-facing changes?

No.