WF from file->open overwrites already open workflow in comfyui_frontend_package 1.43.1

Gonna make it really easy:

Be me.. derp derp derp. Open another workflow.

All seems well.. wait a minute.. what happened?

It's just overwritten and lost. This is a workflow from the library and then a json api workflow is loaded.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-10803-WF-from-file-open-overwrites-already-open-workflow-in-comfyui_frontend_package--3356d73d365081549c18c8277ee79929) by [Unito](https://www.unito.io)

No source files or tests are named. Reproduce the issue by opening a workflow from the library, then loading a JSON API workflow, and trace where the second load replaces the existing workflow. Done means the already open workflow is preserved while the JSON API workflow is loaded without data loss.

Written by the indexing model from the issue text.