Make clone_initializer work better with type checking. (#18)

Also, `str` is preferred to `Text` for type hints.

keras_rs/src/utils/keras_utils.py

@@ -1,18 +1,27 @@
-from typing import Text, Union
+from typing import Union
 
 import keras
 
 
 def clone_initializer(
-    initializer: Union[Text, keras.initializers.Initializer],
+    initializer: Union[str, keras.initializers.Initializer],
 ) -> keras.initializers.Initializer:
     """Clones an initializer to ensure a new seed.
 
+    Args:
+        initializer: The initializer to clone.
+
+    Returns:
+        A cloned initializer if it is clonable, otherwise the original one.
+
     As of tensorflow 2.10, we need to clone user passed initializers when
     invoking them twice to avoid creating the same randomized initialization.
     """
+    if isinstance(initializer, keras.initializers.Initializer):
+        config = initializer.get_config()
+        initializer_class: type[keras.initializers.Initializer] = (
+            initializer.__class__
+        )
+        return initializer_class.from_config(config)
     # If we get a string or dict, just return as we cannot and should not clone.
-    if not isinstance(initializer, keras.initializers.Initializer):
-        return initializer
-    config = initializer.get_config()
-    return initializer.__class__.from_config(config)
+    return initializer