Influx: Query segment menus now position correctly near the bottom of the screen (#60087)

* only open the menu once options are loaded for better positioning

* use !loadState.loading instead of Boolean(loadState.value)

public/app/plugins/datasource/influxdb/components/VisualInfluxQLEditor/Seg.tsx

@@ -111,7 +111,7 @@ const SelSingleLoad = ({ loadOptions, allowCustomValue, onChange, onClose }: Sel
         isLoading={loadState.loading}
         formatCreateLabel={formatCreateLabel}
         autoFocus
-        isOpen
+        isOpen={!loadState.loading}
         onCloseMenu={onClose}
         allowCustomValue={allowCustomValue}
         options={loadState.value ?? []}