Once https://github.com/elastic/elasticsearch/issues/98503 is done, we can use our minimum version numbers in the SystemIndexMappingUpdate service instead of the old `Version` types. Mappings will be updated for a system index when all nodes have a matching descriptor mappings version for a system index, but this version is greater than what's stored in the mappings metadata.
server/src/test/java/org/elasticsearch/cluster/ClusterStateTests.java
"avg_size" : {
                                "total_size_in_bytes" : 120,
                                "shard_count" : 1
                              }
                            },
                            "write_load_forecast" : 8.0
                          }
                        },
                        "index-graveyard" : {
                          "tombstones" : [ ]
                        },
                        "reserved_state" : { }
                      },
                      "routing_table" : {
                        "indices" : {
                          "index" : {
                            "shards" : {
                              "0" : [
                                {
                                  "state" : "STARTED",
                                  "primary" : true,
                                  "node" : "nodeId2",
                                  "relocating_node" : null,
                                  "shard" : 0,
                                  "index" : "index",
                                  "allocation_id" : {
                                    "id" : "%s"
                                  },
                                  "relocation_failure_info" : {
                                    "failed_attempts" : 0