Introduce Uniqcombined64() to Calculate Cardinality Greater Than Uint_max

Why it matters

The new uniqCombined64() function addresses the limitation of existing cardinality functions that overflow when the unique count exceeds UINT_MAX. This allows users to reliably measure distinct elements in massive datasets without losing accuracy due to integer overflow.

How to use it

Users can use the function by calling uniqCombined64(column_name) in aggregate queries where the cardinality might surpass UINT_MAX. It works similarly to other uniqCombined functions but returns a 64-bit result to handle larger counts.