Do not attempt to provide not stringified objects to UI via xcom if pickling is active

[jscheffl]

With this PR the xcom will always be returned as string if XCom pickling is active. Like it was in Airflow 2.9.

closes: #42117

[shahar1]

Could you please add a test? :)

[jkramer-ginkgo]

It would be great to instead have the React JSON view enabled for JSON-serializable Xcom values, and fall back to old logic otherwise. I can try taking a crack at that next week.

[jscheffl]

It would be great to instead have the React JSON view enabled for JSON-serializable Xcom values, and fall back to old logic otherwise. I can try taking a crack at that next week.

Yeah. You can try. We can keep the PR open or you add another PR on top to improve.

Unfortunately the JSON serialization is handled by the underlying framework such that the error is created post return. The only (simple) option that I see is to attempt a serialization and if this is OK then return is native, stryingify as fallback? But then the resulting object needs to be serialized multiple times. Mhm not really good.