Be more verbose when a validation error occurs

[ricardogsilva]

Currently, if there is an error during automated validation of a check, QGIS shows a message informing of a Python error and directs the user to the logs:

Then the logs say this:

_core.QgsProcessingException: There were errors executing the algorithm. 
Traceback (most recent call last):
  File "/home/ricardo/.local/share/QGIS/QGIS3/profiles/default/python/plugins/dataset_qa_workbench/datasetqaworkbench/automation.py", line 90, in perform_automation
    result = qgis.processing.run(algorithm_id, algorithm_parameters)
  File "/home/ricardo/apps/qgis_3_14/share/qgis/python/plugins/processing/tools/general.py", line 106, in run
    return Processing.runAlgorithm(algOrName, parameters, onFinish, feedback, context)
  File "/home/ricardo/apps/qgis_3_14/share/qgis/python/plugins/processing/core/Processing.py", line 198, in runAlgorithm
    raise QgsProcessingException(msg)
_core.QgsProcessingException: There were errors executing the algorithm.

which is also not very informative.

Present a more friendly message to the user that clearly identifies what the problem is