Enable refetch on focus (#1559)

During the integration of react-query we had to disable the refetch on focus option, because it has cleared our input fields on refocusing the browser tab. This problem comes mostly from a wrong use of routes. Often routes were used with the component prop and a anonymous function e.g.:

```jsx
<Route path="/my/route" component={() => <AwesomeComponent />} />
```

This triggers not only rerendering but remounting of the route component every time the parent is rerendered. With the ongoing work on the migration from redux to react-query, we have removed the usage of routes with component functions. So we can now safely enable the option refetch on mount of react-query.

scm-ui/ui-api/src/ApiProvider.tsx

@@ -31,9 +31,7 @@ import { reset } from "./reset";
 const queryClient = new QueryClient({
   defaultOptions: {
     queries: {
-      retry: false,
-      // refetch on focus can reset form inputs
-      refetchOnWindowFocus: false
+      retry: false
     }
   }
 });