MAINT: missing interface

Signed-off-by: George Chen <qchea@amazon.com>

Author: chenqi0805

data-prepper-plugins/encryption-plugin/src/main/java/org/opensearch/dataprepper/plugins/encryption/EncryptionSupplier.java

@@ -0,0 +1,14 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.dataprepper.plugins.encryption;
+
+import org.opensearch.dataprepper.model.encryption.EncryptionEngine;
+
+public interface EncryptionSupplier {
+    EncryptionEngine getEncryptionEngine(String encryptionId);
+
+    EncryptedDataKeySupplier getEncryptedDataKeySupplier(String encryptionId);
+}