Make image converter built

Also add a test for including the image converter in a model.

Author: mattdangerw

keras_hub/src/layers/preprocessing/image_converter.py

@@ -246,6 +246,7 @@ def __init__(
         self.antialias = antialias
         self.bounding_box_format = bounding_box_format
         self.data_format = standardize_data_format(data_format)
+        self.built = True
 
     @property
     def image_size(self):

keras_hub/src/layers/preprocessing/image_converter_test.py

@@ -1,6 +1,7 @@
 import os
 import pathlib
 
+import keras
 import numpy as np
 import pytest
 import tensorflow as tf
@@ -28,6 +29,14 @@ def test_resize_dataset(self):
         batch = ds.batch(2).map(converter).take(1).get_single_element()
         self.assertAllClose(batch, tf.zeros((2, 4, 4, 3)))
 
+    def test_resize_in_model(self):
+        converter = ImageConverter(height=4, width=4, scale=1 / 255.0)
+        inputs = keras.Input(shape=(10, 10, 3))
+        outputs = converter(inputs)
+        model = keras.Model(inputs, outputs)
+        batch = np.ones((1, 10, 10, 3)) * 255.0
+        self.assertAllClose(model(batch), ops.ones((1, 4, 4, 3)))
+
     def test_unbatched(self):
         converter = ImageConverter(
             image_size=(4, 4),