fix(ui): edge case resulting in no node templates when loading workflow, causing failure

Depending on the user behaviour and network conditions, it's possible that we could try to load a workflow before the invocation templates are available.

Fix is simple:
- Use the RTKQ query hook for openAPI schema in App.tsx
- Disable the load workflow buttons until w have templates parsed

invokeai/frontend/web/src/features/workflowLibrary/components/WorkflowLibraryMenu/LoadWorkflowFromGraphMenuItem.tsx

@@ -1,15 +1,19 @@
 import { MenuItem } from '@invoke-ai/ui-library';
+import { useStore } from '@nanostores/react';
+import { $templates } from 'features/nodes/store/nodesSlice';
 import { useLoadWorkflowFromGraphModal } from 'features/workflowLibrary/components/LoadWorkflowFromGraphModal/LoadWorkflowFromGraphModal';
+import { size } from 'lodash-es';
 import { memo } from 'react';
 import { useTranslation } from 'react-i18next';
 import { PiFlaskBold } from 'react-icons/pi';
 
 const LoadWorkflowFromGraphMenuItem = () => {
   const { t } = useTranslation();
+  const templates = useStore($templates);
   const { onOpen } = useLoadWorkflowFromGraphModal();
 
   return (
-    <MenuItem as="button" icon={<PiFlaskBold />} onClick={onOpen}>
+    <MenuItem as="button" icon={<PiFlaskBold />} onClick={onOpen} isDisabled={!size(templates)}>
       {t('workflows.loadFromGraph')}
     </MenuItem>
   );