Track all viser GUI folders to avoid folder duplicates (viewer-beta)

[chungmin99]

With the current "Custom Elements" folder generation, you end up with duplicate folder structures like below:

Given this ViewerText in nerfacto.py

The folder appears as

This is because viser's gui_add_folder creates a unique ID for every folder -- there can exist two folders with the exact same names, but with different IDs --> duplicate structures.

nerfstudio/nerfstudio/viewer_beta/viewer.py

Line 171 in 53037ba

with self.viser_server.add_gui_folder(folder_labels[0]):

This PR changes the viewer element population code to keep track of all the generated folders (with their respective paths), so that the previously folder contexts are used instead of re-generating them (if applicable).

With the PR the structure should be fixed:

, with it also working for nested structures as expected (adding ViewerTexts in nerfacto_field.py):

[kerrj]

sgtm!