GH-8869: Fix NPE in RedisLockRegistry.setExecutor

Fixes: #8869

Do not set the `redisMessageListenerContainer`'s executor in the setter method
since the Redis Message Listener container is not initialised during configuration due to lazy loading

**Cherry-pick to `6.2.x` & `6.0.x`**

Author: Neville Bonavia

spring-integration-redis/src/main/java/org/springframework/integration/redis/util/RedisLockRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -198,8 +198,6 @@ private void setupUnlockMessageListener(RedisConnectionFactory connectionFactory
 	public void setExecutor(Executor executor) {
 		this.executor = executor;
 		this.executorExplicitlySet = true;
-		this.redisMessageListenerContainer.setTaskExecutor(this.executor);
-		this.redisMessageListenerContainer.setSubscriptionExecutor(this.executor);
 	}
 
 	/**

spring-integration-redis/src/test/java/org/springframework/integration/redis/util/RedisLockRegistryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,6 +41,7 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.EnumSource;
 
@@ -52,6 +53,8 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.assertThatNoException;
+import static org.mockito.Mockito.mock;
 
 /**
  * @author Gary Russell
@@ -875,6 +878,13 @@ void testTwoThreadsRemoveAndObtainSameLockSimultaneously(RedisLockType testRedis
 		registry.destroy();
 	}
 
+	@Test
+	void testInitialiseWithCustomExecutor() {
+		RedisLockRegistry redisLockRegistry = new RedisLockRegistry(redisConnectionFactory, "registryKey");
+		redisLockRegistry.setRedisLockType(RedisLockType.PUB_SUB_LOCK);
+		assertThatNoException().isThrownBy(() -> redisLockRegistry.setExecutor(mock()));
+	}
+
 	private Long getExpire(RedisLockRegistry registry, String lockKey) {
 		StringRedisTemplate template = createTemplate();
 		String registryKey = TestUtils.getPropertyValue(registry, "registryKey", String.class);