Hotel heiress Paris Hilton walked out of a Los Angeles-area jail early Tuesday with a big smile on her face after serving 23 days for violating her probation on a reckless driving conviction.The 26-year-old multimillionaire was sentenced to 45 days for the 2006 probation violation, but only served about half the term, gaining credit for good behavior."This is by far the hardest thing I have ever done," she said in a statement. "I have had a lot of time to reflect, and have already learned a bitter, but important lesson from this experience."Hilton has said in interviews that her time