Fix keras version problem (#15265)

* Fix keras version problem

* Fix keras version problem

* Fix keras version problem

* Fix keras version problem

* Fix keras version problem

* Fix keras version problem

* Fix keras version problem

Author: haoyang9804

python/tvm/relay/frontend/keras.py

@@ -1526,12 +1526,19 @@ def _convert_layer(keras_layer, etab, scope=""):
             raise ValueError("Keras frontend currently supports tensorflow backend only.")
         if keras.backend.image_data_format() != "channels_last":
             raise ValueError("Keras frontend currently supports data_format = channels_last only.")
-        expected_model_class = keras.engine.training.Model
-        if hasattr(keras.engine, "InputLayer"):
-            input_layer_class = keras.engine.InputLayer
+        try:
+            import keras.engine as E
+        except ImportError:
+            try:
+                import keras.src.engine as E
+            except ImportError:
+                raise ImportError("Cannot find Keras's engine")
+        expected_model_class = E.training.Model
+        if hasattr(E, "InputLayer"):
+            input_layer_class = E.InputLayer
         else:
             # TFlite >=2.6
-            input_layer_class = keras.engine.input_layer.InputLayer
+            input_layer_class = E.input_layer.InputLayer
     else:
         # Importing from Tensorflow Keras (tf.keras)
         try: