Remove unused upgrade actions (#62552)

These actions were almost completely removed in #40075 but a couple of
classes were left in place. This commit completes their removal.

Author: DaveCTurner

x-pack/plugin/core/src/main/java/org/elasticsearch/protocol/xpack/migration/IndexUpgradeInfoRequest.java

@@ -256,8 +256,6 @@
 import org.elasticsearch.xpack.core.transform.transforms.TimeSyncConfig;
 import org.elasticsearch.xpack.core.transform.transforms.TransformState;
 import org.elasticsearch.xpack.core.transform.transforms.TransformTaskParams;
-import org.elasticsearch.xpack.core.upgrade.actions.IndexUpgradeAction;
-import org.elasticsearch.xpack.core.upgrade.actions.IndexUpgradeInfoAction;
 import org.elasticsearch.xpack.core.vectors.VectorsFeatureSetUsage;
 import org.elasticsearch.xpack.core.votingonly.VotingOnlyNodeFeatureSetUsage;
 import org.elasticsearch.xpack.core.watcher.WatcherFeatureSetUsage;
@@ -427,9 +425,6 @@ public List<ActionType<? extends ActionResponse>> getClientActions() {
                 CreateApiKeyAction.INSTANCE,
                 InvalidateApiKeyAction.INSTANCE,
                 GetApiKeyAction.INSTANCE,
-                // upgrade
-                IndexUpgradeInfoAction.INSTANCE,
-                IndexUpgradeAction.INSTANCE,
                 // watcher
                 PutWatchAction.INSTANCE,
                 DeleteWatchAction.INSTANCE,