Update utils_app.py

Just to make sure it really sets it in right scope 🤞

utils_app.py

@@ -4,6 +4,8 @@ from tensorflow import keras
 import tensorflow as tf
 import gradio as gr
 
+keras.mixed_precision.set_global_policy("mixed_float16")
+
 keras_model_list = [
     "keras-dreambooth/keras_diffusion_lowpoly_world",
 
@@ -28,8 +30,6 @@ def keras_stable_diffusion(
     width:int,
     ):
         
-    keras.mixed_precision.set_global_policy("mixed_float16")
-
     sd_dreambooth_model = models.StableDiffusion(
         img_width=height, 
         img_height=width