Add PipelineAnalysisContext message to support pipeline analysis during Spark Connect query execution

### What changes were proposed in this pull request?
This PR introduces a new protobuf message, PipelineAnalysisContext, in ect/common/src/main/protobuf/spark/connect/pipelines.proto.

### Why are the changes needed?
Special handling is needed for spark.sql in certain contexts. This proto provides a foundation for passing such context in future.

### Does this PR introduce _any_ user-facing change?
No, it only adds an internal protobuf message.

### How was this patch tested?
Verified through protobuf compilation and existing test coverage.

### Was this patch authored or co-authored using generative AI tooling?
No.

Closes #52685 from cookiedough77/jessie.luo-data/add-analysis-context-proto.

Authored-by: Jessie Luo <[email protected]>
Signed-off-by: Sandy Ryza <[email protected]>

Author: cookiedough77