fix(api-docs): set url explicitly to an empty string

The url argument is undefined when it is not explicitly set to an empty string. An undefined url is
causing the swagger UI to fail on match checks.

fixes #8895

Signed-off-by: Dominik Schwank <dominik.schwank@sda.se>

plugins/api-docs/src/components/OpenApiDefinitionWidget/OpenApiDefinition.tsx

@@ -148,7 +148,7 @@ export const OpenApiDefinition = ({ definition }: OpenApiDefinitionProps) => {
 
   return (
     <div className={classes.root}>
-      <SwaggerUI spec={def} deepLinking />
+      <SwaggerUI spec={def} url="" deepLinking />
     </div>
   );
 };