Fix job type assignment and clean up testfunctions file.

Updated job type to reference `experiment.type` in `processing.py` for accurate data handling. Cleaned up and streamlined `testfunctions.ipynb` by removing outdated and redundant code, improving readability and usability.

backend/app/routers/processing.py

@@ -41,7 +41,10 @@ async def job_event_generator(db: Session):
                 experiment_parameters=experiment.beamline_parameters
                 if experiment
                 else None,
-                slurm_id=None,
+                filepath=experiment.dataset.get("filepath")
+                if experiment and experiment.dataset
+                else None,
+                slurm_id=job.slurm_id,
             )
 
             job_items.append(job_item)