refactor(app.py): move model and uid initialization inside function

app.py

@@ -4,11 +4,11 @@ from sbv2_bindings import TTSModel
 
 bert = hf_hub_download("googlefan/sbv2_onnx_models", "deberta.onnx")
 tokenizer = hf_hub_download("googlefan/sbv2_onnx_models", "tokenizer.json")
-model = TTSModel.from_path(bert, tokenizer)
-uid = "default"
 
 
 def load_and_synthesize(text: str, path: str, sdp: float = 0.0, speed: float = 1.0):
+    model = TTSModel.from_path(bert, tokenizer)
+    uid = "default"
     path = path.split("/")
     filename = path[-1]
     repo_id = "/".join(path[:-1])