chore: Update flash-attn installation command in app.py

app.py

@@ -4,7 +4,7 @@ import torch
 import gradio as gr
 from threading import Thread
 import subprocess
-subprocess.run('pip install -U flash-attn', shell=True)
+subprocess.run('pip install -U flash-attn --no-build-isolation', env={'FLASH_ATTENTION_SKIP_CUDA_BUILD': "TRUE"}, shell=True)
 
 models_available = [
     "MohamedRashad/Arabic-Orpo-Llama-3-8B-Instruct",