Test step fragment "Validate flight sharing" does not validate some issues properly

[mickmis]

Describe the bug
Refactoring of uss_qualifier/scenarios/astm/utm/test_steps.py by #376 introduced two issues in the validation of the operational intent details implemented in _evaluate_op_intent_validation.

Because arguments passed to add are not properly constructed as OpIntentValidationFailure type, the add has no effect.

Validation of number of vertices in the operational intent won't surface:

monitoring/monitoring/uss_qualifier/scenarios/astm/utm/test_steps.py

Lines 483 to 490 in d9c8ea8

	if n_vertices > 10000:
	details = (
	f"Operational intent {oi_full.reference.id} had too many total vertices - {n_vertices}",
	)
	validation_failures.add(
	validation_failure_type=OpIntentValidationFailureType.VertexCount,
	error_text=details,
	)

(Some) incorrect JSON errors won't surface:

monitoring/monitoring/uss_qualifier/scenarios/astm/utm/test_steps.py

Lines 491 to 495 in d9c8ea8

	except (KeyError, ValueError) as e:
	validation_failures.add(
	validation_failure_type=OpIntentValidationFailureType.DataFormat,
	error_text=e,
	)

("some" because validation with the OpenAPI definition is done before and this one will surface properly).

Possible solution

                    validation_failures.add(
                        OpIntentValidationFailure(
                            validation_failure_type=OpIntentValidationFailureType.XXX,
                            error_text=xxx,
                        )
                    )