Fixes device run-ro command failure when response is missing some fields, and updates tests (#8813)

* Adds check and tests for empty fields

* Updates link

Author: ejiadedeji

src/managednetworkfabric/HISTORY.rst

@@ -3,6 +3,10 @@
 Release History
 ===============
 
+8.0.0b4
+++++++
+* Fixes 'device run-ro' command for missing fields in the response.
+
 8.0.0b3
 ++++++
 * Adding custom output formatting for 'device' run-ro command

src/managednetworkfabric/azext_managednetworkfabric/operations/custom_properties.py

@@ -30,8 +30,12 @@ def _output(parent_cmd, *args, **kwargs):  # pylint: disable=unused-argument
         op_response = parent_cmd.ctx.vars.instance.properties.to_serialized_data()
 
         new_properties = {}
-        new_properties["configurationState"] = op_response["configurationState"]
-        new_properties["outputUrl"] = op_response["outputUrl"]
+
+        if has_value(parent_cmd.ctx.vars.instance.properties.configuration_state):
+            new_properties["configurationState"] = op_response["configurationState"]
+
+        if has_value(parent_cmd.ctx.vars.instance.properties.output_url):
+            new_properties["outputUrl"] = op_response["outputUrl"]
 
         if has_value(
             parent_cmd.ctx.vars.instance.properties.device_configuration_preview
@@ -50,6 +54,6 @@ def _output(parent_cmd, *args, **kwargs):  # pylint: disable=unused-argument
                 logger.warning(json_string)
                 new_properties["deviceConfigurationPreview"] = json_string
         else:
-            new_properties["deviceConfigurationPreview"] = "{}"
+            new_properties["deviceConfigurationPreview"] = {}
 
         return new_properties