Run button disabled saying workflow contains unsupported nodes if anything except core nodes are in workflow.

### Temp Workaround by [henrikvilhelmberglund](https://github.com/henrikvilhelmberglund)
> you can open the devtools inspector, click on the button, and remove the `disabled` attribute in the `` tag.

### Prerequisites

- [x] I am running the latest version of ComfyUI
- [x] I have searched existing issues to make sure this isn't a duplicate
- [x] I have tested with all custom nodes disabled ([see how](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled))

### What happened?

The following cause the Run button to be disabled.
- Create new tab
- Open workflow
- Change tab to a workflow that is either empty or contains any custom node

The run button also doesn't update if it is available until you change to a different tab and come back or reload the page.

Workflows with custom nodes can be run by copy and pasting all the nodes into a currently enabled tab but tabbing away and back will break it.

Even without custom nodes installed then creating a new tab and building a workflow only works after creating a second tab to temporarily open.

### Steps to Reproduce

1. Load\Create a workflow with core nodes only
2. Add a custom node to working workflow(even if not connected)
3. Create a second tab
4. Change back to workflow tab and it is no longer enabled.

### How is this affecting you?

Workflow won't execute

### ComfyUI Frontend Version

1.33.1

### Browser

Firefox

### Console Errors

```javascript
No errors but following warnings

Invalid URI. Load of media resource failed. 2 127.0.0.1:8188
[ComfyUI Notice] "scripts/widgets.js" is an internal module, not part of the public API. Future updates may break this import. widgets.js:2:9
[ComfyUI Notice] "scripts/pnginfo.js" is an internal module, not part of the public API. Future updates may break this import. pnginfo.js:2:9
[ComfyUI Notice] "extensions/core/clipspace.js" is an internal module, not part of the public API. Future updates may break this import. clipspace.js:2:9
[ComfyUI Notice] "scripts/utils.js" is an internal module, not part of the public API. Future updates may break this import. utils.js:2:9
[ComfyUI Deprecated] Importing from "extensions/core/groupNode.js" is deprecated and will be removed in v1.34. groupNode.js:2:9
[ComfyUI Notice] "extensions/core/widgetInputs.js" is an internal module, not part of the public API. Future updates may break this import. widgetInputs.js:2:9
[ComfyUI Deprecated] Importing from "scripts/ui/components/buttonGroup.js" is deprecated and will be removed in v1.34. buttonGroup.js:2:9
[ComfyUI Deprecated] Importing from "scripts/ui/components/button.js" is deprecated and will be removed in v1.34. button.js:2:9
Empty components: policy ignored components-manager.js:770:11
Trying to unset non-exist keybinding: {"commandId":"Comfy.ClearWorkflow","combo":{"key":"Backspace","ctrl":false,"alt":false,"shift":false}} keybindingStore.ts:246:15
```

### Logs

```shell

```

### Additional Context

Tried on Chrome and Firefox

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-6766-Run-button-disabled-saying-workflow-contains-unsupported-nodes-if-anything-except-core-2b16d73d3650810292e0e41027f53517) by [Unito](https://www.unito.io)