Update ibm_catalog.json (#641)

Author: ocofaigh

ibm_catalog.json

@@ -191,18 +191,6 @@
                             "key": "ssh_public_key",
                             "required": true
                         },
-                        {
-                            "key": "existing_ssh_key_name",
-                            "required": false,
-                            "custom_config": {
-                                "config_constraints": {
-                                    "valueType": "name"
-                                },
-                                "grouping": "deployment",
-                                "original_grouping": "deployment",
-                                "type": "vpc_ssh_key"
-                            }
-                        },
                         {
                             "hidden": true,
                             "key": "teleport_domain"