NPA-5537: update button link again

Author: LeoKHoward

specification/validated-relationships-service-api.yaml

@@ -141,8 +141,7 @@ info:
     * only covers a limited set of scenarios
     * is open access, so does not allow you to test authorisation
 
-    [<img src="https://run.pstmn.io/button.svg" alt="Run In Postman" style="width: 128px; height: 32px;">](https://run.pstmn.io/button.svg)](https://app.getpostman.com/run-collection/26376766-4fd91043-1337-4f8b-92c9-96c597b343c8?action=collection%2Ffork&collection-url=entityId%3D26376766-4fd91043-1337-4f8b-92c9-96c597b343c8%26entityType%3Dcollection%26workspaceId%3D8fc7bffa-055c-43e2-b94b-da0fdce3aa4b)
-
+    [<img src="https://run.pstmn.io/button.svg" alt="Run In Postman" style="width: 128px; height: 32px;">](https://app.getpostman.com/run-collection/26376766-4fd91043-1337-4f8b-92c9-96c597b343c8?action=collection%2Ffork&collection-url=entityId%3D26376766-4fd91043-1337-4f8b-92c9-96c597b343c8%26entityType%3Dcollection%26workspaceId%3D8fc7bffa-055c-43e2-b94b-da0fdce3aa4b)
     ### Integration testing
 
     Our [integration test environment](https://digital.nhs.uk/developer/guides-and-documentation/testing#integration-testing)