[V3] convert nodes_load_3d.py to V3 schema

[bigcat88]

Implementation of the Preview3D node was moved to internal folder.

Nodes were tested after conversion:

Objects git diff:

diff --git a/v3_object_info.json b/master_object_info.json
index 4a087e5..342af8a 100644
--- a/v3_object_info.json
+++ b/master_object_info.json
@@ -25564,16 +25564,8 @@
         "input": {
             "required": {
                 "model_file": [
-                    "COMBO",
+                    [],
                     {
-                        "multiselect": false,
-                        "options": [],
                         "file_upload": true
                     }
                 ],
@@ -25633,23 +25625,13 @@
             "camera_info",
             "recording_video"
         ],
-        "output_tooltips": [
-            null,
-            null,
-            null,
-            null,
-            null,
-            null
-        ],
         "name": "Load3D",
         "display_name": "Load 3D & Animation",
         "description": "",
         "python_module": "comfy_extras.nodes_load_3d",
         "category": "3d",
         "output_node": false,
-        "deprecated": false,
-        "experimental": true,
-        "api_node": false
+        "experimental": true
     },
     "Preview3D": {
         "input": {
@@ -25671,14 +25653,6 @@
                     "IMAGE",
                     {}
                 ]
-            },
-            "hidden": {
-                "prompt": [
-                    "PROMPT"
-                ],
-                "extra_pnginfo": [
-                    "EXTRA_PNGINFO"
-                ]
             }
         },
         "input_order": {
@@ -25688,25 +25662,18 @@
             "optional": [
                 "camera_info",
                 "bg_image"
-            ],
-            "hidden": [
-                "prompt",
-                "extra_pnginfo"
             ]
         },
         "output": [],
         "output_is_list": [],
         "output_name": [],
-        "output_tooltips": [],
         "name": "Preview3D",
         "display_name": "Preview 3D & Animation",
         "description": "",
         "python_module": "comfy_extras.nodes_load_3d",
         "category": "3d",
         "output_node": true,
-        "deprecated": false,
-        "experimental": true,
-        "api_node": false
+        "experimental": true
     },
     "EmptyCosmosLatentVideo": {
         "input": {

[bigcat88]

+label: Core

[Kosinkadink]

minimally tested on my end, works, object_info diff looks good. since no custom nodes import this, merging immediately