New HLL States for count_distinct in ES|QL #142333
Description
Currently, we share the HyperLogLog implementation between search and ES|QL. However, serialization and merging could be made more efficient by processing in bulk rather than one by one in ES|QL. Additionally, we should consider supporting higher precision, allowing dynamic growth in each group until a memory limit is reached, instead of rejecting requests up front. For example, with fewer groups, it is acceptable to support higher precision, but for queries with many groups, users should use lower/default precision. Nevertheless, we should maintain a hard limit, which should be higher than the current one.