[FEATURE]: Create demo for Spark Structured Streaming

[mwojtyczka]

Is there an existing issue for this?

• I have searched the existing issues

Problem statement

We currently provide streaming demo for DLT (Declarative Pipelines) only.

Proposed Solution

Create a demo for Spark Structured Streaming. This can be based on the existing dlt demo to keep it simple and neat: https://github.com/databrickslabs/dqx/blob/v0.7.1/demos/dqx_dlt_demo.py

Additional Context

No response

[mwojtyczka]

Added already. Will be available after next release.