fix: made kms_endpoint_type a dropdown in DA (#680)

Author: ocofaigh

ibm_catalog.json

@@ -360,7 +360,17 @@
               "key": "existing_cluster_kms_key_crn"
             },
             {
-              "key": "kms_endpoint_type"
+              "key": "kms_endpoint_type",
+              "options": [
+                {
+                  "displayname": "Public",
+                  "value": "public"
+                },
+                {
+                  "displayname": "Private",
+                  "value": "private"
+                }
+              ]
             },
             {
               "key": "cluster_key_name"