fix: updated the DA to default to the "Default" resource group (#801)

Author: piyush117

ibm_catalog.json

@@ -571,6 +571,8 @@
             {
               "key": "existing_resource_group_name",
               "display_name": "resource_group",
+              "default_value": "Default",
+              "description": "The name of an existing resource group to provision the resources.",
               "custom_config": {
                 "type": "resource_group",
                 "grouping": "deployment",
@@ -1296,6 +1298,8 @@
             {
               "key": "existing_resource_group_name",
               "display_name": "resource_group",
+              "default_value": "Default",
+              "description": "The name of an existing resource group to provision the resources.",
               "custom_config": {
                 "type": "resource_group",
                 "grouping": "deployment",