Remove @⁠FunctionalInterface declaration from BeanOverrideProcessor

Closes gh-34259

Author: sbrannen

spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -36,7 +36,6 @@
  * @author Sam Brannen
  * @since 6.2
  */
-@FunctionalInterface
 public interface BeanOverrideProcessor {
 
 	/**