corrected the example code in unit_normalization.py (#19845)

Added missing closing bracket and exact output value in example code after replicating the code.

Author: keerthanakadiri

keras/src/layers/normalization/unit_normalization.py

@@ -14,8 +14,9 @@ class UnitNormalization(Layer):
 
     >>> data = np.arange(6).reshape(2, 3)
     >>> normalized_data = keras.layers.UnitNormalization()(data)
-    >>> print(np.sum(normalized_data[0, :] ** 2)
-    1.0
+    >>> print(np.sum(normalized_data[0, :] ** 2))
+    0.99999994
+
 
     Args:
         axis: Integer or list/tuple. The axis or axes to normalize across.