Fix around implicit

Multiple fixes around implicit indices. The schema shown or stored (keeper metadata) won't include implicit indices, such as the ones created by settings add_minmax_index_for_numeric_columns or add_minmax_index_for_string_columns. This might cause metadata errors when a ReplicatedMergeTree table is created or updated in a newer version, while there is a replica in an older release. For those cases send DDLs to the old replica until the cluster is upgraded completely. #91429 (Raúl Marín).