Fix cluster.routing.allocation.enable and cluster.routing.rebalance.enable casing (#28037)

Fixes the default value of cluster.routing.allocation.enable and cluster.routing.rebalance.enable to be lower-case.

Author: kel

core/src/main/java/org/elasticsearch/cluster/routing/allocation/decider/EnableAllocationDecider.java

@@ -63,17 +63,17 @@ public class EnableAllocationDecider extends AllocationDecider {
     public static final String NAME = "enable";
 
     public static final Setting<Allocation> CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING =
-        new Setting<>("cluster.routing.allocation.enable", Allocation.ALL.name(), Allocation::parse,
+        new Setting<>("cluster.routing.allocation.enable", Allocation.ALL.toString(), Allocation::parse,
             Property.Dynamic, Property.NodeScope);
     public static final Setting<Allocation> INDEX_ROUTING_ALLOCATION_ENABLE_SETTING =
-        new Setting<>("index.routing.allocation.enable", Allocation.ALL.name(), Allocation::parse,
+        new Setting<>("index.routing.allocation.enable", Allocation.ALL.toString(), Allocation::parse,
             Property.Dynamic, Property.IndexScope);
 
     public static final Setting<Rebalance> CLUSTER_ROUTING_REBALANCE_ENABLE_SETTING =
-        new Setting<>("cluster.routing.rebalance.enable", Rebalance.ALL.name(), Rebalance::parse,
+        new Setting<>("cluster.routing.rebalance.enable", Rebalance.ALL.toString(), Rebalance::parse,
             Property.Dynamic, Property.NodeScope);
     public static final Setting<Rebalance> INDEX_ROUTING_REBALANCE_ENABLE_SETTING =
-        new Setting<>("index.routing.rebalance.enable", Rebalance.ALL.name(), Rebalance::parse,
+        new Setting<>("index.routing.rebalance.enable", Rebalance.ALL.toString(), Rebalance::parse,
             Property.Dynamic, Property.IndexScope);
 
     private volatile Rebalance enableRebalance;
@@ -228,6 +228,11 @@ public static Allocation parse(String strValue) {
                 }
             }
         }
+
+        @Override
+        public String toString() {
+            return name().toLowerCase(Locale.ROOT);
+        }
     }
 
     /**
@@ -255,6 +260,11 @@ public static Rebalance parse(String strValue) {
                 }
             }
         }
+
+        @Override
+        public String toString() {
+            return name().toLowerCase(Locale.ROOT);
+        }
     }
 
 }