Remove Unused Snapshot Status Values (#54893) (#54906)

* Remove Unused Snapshot Status Values

This is a left-over from before #41940 when we used the same status enum for the shards
and the snapshots overall. The two removed values were never used on the shard level
so we can simply remove them here.

Author: original-brownbear

server/src/main/java/org/elasticsearch/cluster/SnapshotsInProgress.java

@@ -427,9 +427,7 @@ public enum State {
         STARTED((byte) 1, false),
         SUCCESS((byte) 2, true),
         FAILED((byte) 3, true),
-        ABORTED((byte) 4, false),
-        MISSING((byte) 5, true),
-        WAITING((byte) 6, false);
+        ABORTED((byte) 4, false);
 
         private final byte value;
 
@@ -460,10 +458,6 @@ public static State fromValue(byte value) {
                     return FAILED;
                 case 4:
                     return ABORTED;
-                case 5:
-                    return MISSING;
-                case 6:
-                    return WAITING;
                 default:
                     throw new IllegalArgumentException("No snapshot state for value [" + value + "]");
             }

server/src/test/java/org/elasticsearch/cluster/ClusterStateDiffIT.java

@@ -716,7 +716,7 @@ public ClusterState.Custom randomCreate(String name) {
                                 new Snapshot(randomName("repo"), new SnapshotId(randomName("snap"), UUIDs.randomBase64UUID())),
                                 randomBoolean(),
                                 randomBoolean(),
-                                SnapshotsInProgress.State.fromValue((byte) randomIntBetween(0, 6)),
+                                randomFrom(SnapshotsInProgress.State.values()),
                                 Collections.emptyList(),
                                 Math.abs(randomLong()),
                                 (long) randomIntBetween(0, 1000),