make broken connections more obvious by removing controls

tank-frontend/src/Controls.tsx

@@ -58,6 +58,9 @@ export default function Controls({player}: { player: string }) {
         };
     }, [readyState]);
 
+    if (readyState != ReadyState.OPEN)
+        return <></>;
+
     return <div className="Controls flex-row">
         <div className="flex-column Controls-Container">
             <h3>Move</h3>

tank-frontend/src/MapChooser.tsx

@@ -36,6 +36,9 @@ export default function MapChooser() {
         postMap.mutate(chosenMap);
     };
 
+    if (query.isError)
+        return <></>;
+
     const disabled = !query.isSuccess || postMap.isPending;
 
     return <select className="MapChooser-DropDown" onChange={onChange} disabled={disabled}>

tank-frontend/src/PlayerInfo.tsx

@@ -57,7 +57,7 @@ export default function PlayerInfo({player}: { player: string }) {
         sendMessage('');
     }, [readyState, shouldSendMessage]);
 
-    if (!lastJsonMessage)
+    if (!lastJsonMessage || readyState !== ReadyState.OPEN)
         return <></>;
 
     return <Column className="PlayerInfo">