[BUG] Auto slicing is not supported for DeleteByQuery, Reindex, and UpdateByQuery

[fs-chris]

What is the bug?

The API does not allow defining auto-slicing for DeleteByQueryRequest, ReindexRequest, and UpdateByQueryRequest.
JavaDoc suggests using 'auto' but only Long value is accepted.

		/**
		 * The number of slices this task should be divided into. Defaults to 1, meaning
		 * the task isn't sliced into subtasks. Can be set to <code>auto</code>.
		 * <p>
		 * API name: {@code slices}
		 */
		public final Builder slices(@Nullable Long value) {
			this.slices = value;
			return this;
		}

How can one reproduce the bug?

n/a

What is the expected behavior?

Add support for configuring automatic slicing.

What is your host/environment?

Linux/Windows, Java 17
OpenSearch server 2.4.0
OpenSearch client 2.1.0

Do you have any screenshots?

n/a

Do you have any additional context?

[wbeckler]

This is a good catch. Feel free to submit a PR.