Stateless thread pool for upload warming (#127974)

Relates ES-11323

Author: kingherc

server/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java

@@ -204,6 +204,7 @@ private class ShutdownLogger {
     public static final String STATELESS_SHARD_WRITE_THREAD_NAME = "stateless_shard_write";
     public static final String STATELESS_CLUSTER_STATE_READ_WRITE_THREAD_NAME = "stateless_cluster_state";
     public static final String STATELESS_SHARD_PREWARMING_THREAD_NAME = "stateless_prewarm";
+    public static final String STATELESS_SHARD_UPLOAD_PREWARMING_THREAD_NAME = "stateless_upload_prewarm";
     public static final String SEARCHABLE_SNAPSHOTS_CACHE_FETCH_ASYNC_THREAD_NAME = "searchable_snapshots_cache_fetch_async";
     public static final String SEARCHABLE_SNAPSHOTS_CACHE_PREWARMING_THREAD_NAME = "searchable_snapshots_cache_prewarming";
 
@@ -2187,6 +2188,7 @@ private void assertSnapshotOrStatelessPermittedThreadPool() {
             STATELESS_SHARD_WRITE_THREAD_NAME,
             STATELESS_CLUSTER_STATE_READ_WRITE_THREAD_NAME,
             STATELESS_SHARD_PREWARMING_THREAD_NAME,
+            STATELESS_SHARD_UPLOAD_PREWARMING_THREAD_NAME,
             SEARCHABLE_SNAPSHOTS_CACHE_FETCH_ASYNC_THREAD_NAME,
             SEARCHABLE_SNAPSHOTS_CACHE_PREWARMING_THREAD_NAME
         );