fix(python): Normalize by default in Series.entropy like Expr.entropy…

… does (#18493)

py-polars/polars/series/series.py

@@ -2565,7 +2565,7 @@ def unique_counts(self) -> Series:
         ]
         """
 
-    def entropy(self, base: float = math.e, *, normalize: bool = False) -> float | None:
+    def entropy(self, base: float = math.e, *, normalize: bool = True) -> float | None:
         """
         Computes the entropy.