revert(config): use `float16` default torch dtype

config.json

@@ -17,7 +17,7 @@
   "partial_rotary_factor": 0.25,
   "rope_theta": 10000,
   "tie_word_embeddings": false,
-  "torch_dtype": "bfloat16",
+  "torch_dtype": "float16",
   "transformers_version": "4.38.0",
   "use_cache": true,
   "use_qkv_bias": true,