[Enhancement] (nereids)implement showREplicaDistributionCommand in nereids

[LiBinfeng-01]

showREplicaDistribution command is supported in legacy planner but not in nereids(new doris fe planner). you need implement the following showREplicaDistribution command in nereids:
unsupportedshowREplicaDistributionStatement
SHOW REPLICA DISTRIBUTION FROM baseTableRef

[Vallishp]

Its similar to #42837 i will pick it