test: sync default.json fixture with defaultGraph models metadata

The locale-export test loads default.json then reloads the page
(which uses defaultGraph.ts). Since defaultGraph.ts now embeds
models metadata in the CheckpointLoader properties, the fixture
must match to avoid a mismatch between the English and Chinese
exports.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

browser_tests/assets/default.json

@@ -119,7 +119,15 @@
         { "name": "CLIP", "type": "CLIP", "links": [3, 5], "slot_index": 1 },
         { "name": "VAE", "type": "VAE", "links": [8], "slot_index": 2 }
       ],
-      "properties": {},
+      "properties": {
+        "models": [
+          {
+            "name": "v1-5-pruned-emaonly-fp16.safetensors",
+            "url": "https://huggingface.co/Comfy-Org/stable-diffusion-v1-5-archive/resolve/main/v1-5-pruned-emaonly-fp16.safetensors?download=true",
+            "directory": "checkpoints"
+          }
+        ]
+      },
       "widgets_values": ["v1-5-pruned-emaonly-fp16.safetensors"]
     }
   ],