Added New Function Isvalidutf8 for Checking Whether a Set of Bytes Is Correctly Utf-8 Encoded

Why it matters

This feature addresses the need to validate UTF-8 encoding correctness in data, helping users identify and handle encoding errors effectively within ClickHouse.

How to use it

Use the isValidUTF8 function in your queries by passing the byte sequence or string you want to check. It returns a boolean indicating whether the input is valid UTF-8 encoded bytes.