Update config.json

Include the torch_dtype in the model config.json.
This matches the config.json of similar releases (e.g.,Mistral-Large-Instruct-2407, Mistral-Small-24B-Instruct-2501).

config.json

@@ -19,6 +19,7 @@
   "rope_theta": 1000000.0,
   "sliding_window": null,
   "tie_word_embeddings": false,
+  "torch_dtype": "bfloat16",
   "transformers_version": "4.46.2",
   "use_cache": true,
   "vocab_size": 32768