[ServiceBus] Connection error with unknown condition code to be ServiceBusConnectionError instead of ServiceBusError

[yunhaoling]

Right now, if there's a connection error happening with condition unknown, a ServiceBusError is throwed due to the current condition based exception handling -- condition code b"amqp:unknown-error" is not in the condition-error mapping and default to ServiceBusError.

However, I think this could be improved by raising ServiceBusConnectionError if the error condition is unknown to be more detailed.

This is a non-breaking change.

To be more specific, it's this part of the code that should be improved:

azure-sdk-for-python/sdk/servicebus/azure-servicebus/azure/servicebus/exceptions.py

Lines 83 to 108 in 21e154b

	def _handle_amqp_exception_with_condition(
	logger,
	condition,
	description,
	exception=None,
	status_code=None
	):
	#
	# handling AMQP Errors that have the condition field or the mgmt handler
	logger.info("AMQP error occurred: (%r), condition: (%r), description: (%r).", exception, condition, description)
	if condition == AMQPErrorCodes.NotFound:
	# handle NotFound error code
	error_cls = ServiceBusCommunicationError \
	if isinstance(exception, AMQPErrors.AMQPConnectionError) else MessagingEntityNotFoundError
	elif condition == AMQPErrorCodes.ClientError and 'timed out' in str(exception):
	# handle send timeout
	error_cls = OperationTimeoutError
	else:
	# handle other error codes
	error_cls = _ERROR_CODE_TO_ERROR_MAPPING.get(condition, ServiceBusError)
	error = error_cls(message=description, error=exception, condition=condition, status_code=status_code)
	if condition in _NO_RETRY_CONDITION_ERROR_CODES:
	error._retryable = False # pylint: disable=protected-access
	return error