[Feature Request]: Option to force show docs fallback content on node's help page

### Is there an existing issue for this?

- [x] I have searched the existing issues and checked the recent builds/commits

### What would your feature do ?

Currently when a doc is added for a node (i.e. as described here: https://docs.comfy.org/custom-nodes/help_page) then the nice fallback content with the node's inputs and outputs is no longer shown.

The request here is to allow showing the fallback content (i.e. at the bottom of the help page) regardless whether docs are already provided or not.
Say, by a a new flag in node definition i.e. `SHOW_FALLBACK_DESCRIPTION` or something
This will save documentation maintainers from manually keeping track of inputs and outputs updates if their documentaion displays them.

### Proposed workflow

1. Node developer adds a flag
```SHOW_FALLBACK_DESCRIPTION = True```
and the value of the flag is then passed to front end.
2. When help page for the node is displayed the NodeHelpPage.vue template checks whether the flag is set to true (on top of whether the docs don't exist) and displays the fallback-content if yes.

### Additional information

_No response_

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-4300-Feature-Request-Option-to-force-show-docs-fallback-content-on-node-s-help-page-2216d73d365081259ba1eff0cb1c09ae) by [Unito](https://www.unito.io)

Read the existing docs and fallback-content condition in NodeHelpPage.vue, then trace how node definition metadata reaches the frontend. Done means a true flag makes the fallback content appear even when docs exist, while existing behavior remains unchanged when the flag is absent or false.

Written by the indexing model from the issue text.