correct script and swagger (microsoft#2631)

* Update apiProperties.json

* Update script.csx

* Update script.csx

Author: sfc-gh-mmarzillo

certified-connectors/snowflake/apiProperties.json

@@ -48,15 +48,6 @@
       "Convert"
     ],
     "capabilities": [],
-    "policyTemplateInstances": [
-      {
-        "parameters": {
-          "x-ms-apimTemplateParameter.urlTemplate": "https://@connectionParameters('instanceURL')"
-        },
-        "templateId": "dynamichosturl",
-        "title": "instanceURL"
-      }
-    ],
     "publisher": "Koch, Rene",
     "stackOwner": "Snowflake Inc."
   }

certified-connectors/snowflake/script.csx

@@ -10,7 +10,7 @@ public class Script : ScriptBase
 
         // Check if the operation ID matches what is specified in the OpenAPI definition of the connector
         // Presence is enforced in swagger
-        var domain = this.Context.Request.Headers.GetValues("Domain").First();
+        var domain = this.Context.Request.Headers.GetValues("Instance").First();
 
         var uriBuilder = new UriBuilder(this.Context.Request.RequestUri);
         uriBuilder.Host = domain;