[bug] Manager UI server dropdown cleanup

[maia-iyer]

Environment:

I deployed Tornjak backend in a local Kind cluster and the Tornjak manager backend is running locally at port 50000
Then I ran:

cd frontend
REACT_APP_API_SERVER_URI=http://localhost:50000/ REACT_APP_TORNJAK_MANAGER=true npm start

To start the frontend with the manager UI.

Error

The dropdown is working, but it's not the cleanest. Upon startup this is what it looks like:

And once one is selected, it looks like:

So it seems there's a permanently grayed out Select an Option and there's also a permanently grayed out selection that states whatever is selected.

[mamy-CS]

/assign @EdgarAllan-Bro