Streamfield: don't render values container unless it has values

app/soapbox/components/ui/streamfield/streamfield.tsx

@@ -65,6 +65,7 @@ const Streamfield: React.FC<IStreamfield> = ({
         {hint && <Text size='xs' theme='muted'>{hint}</Text>}
       </Stack>
 
+      {(values.length > 0) && (
         <Stack>
           {values.map((value, i) => (
             <HStack space={2} alignItems='center'>
@@ -81,6 +82,7 @@ const Streamfield: React.FC<IStreamfield> = ({
             </HStack>
           ))}
         </Stack>
+      )}
 
       {onAddItem && (
         <Button