Remove APIs deprecated for removal in 6.1

This is the first commit that removes deprecated APIs.

Subsequent commits will remove additional deprecated APIs.

See gh-29449

spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -95,13 +95,6 @@ public class MockClientHttpRequest extends AbstractClientHttpRequest implements
 		return this.httpMethod;
 	}
 
-	@SuppressWarnings("removal")
-	@Override
-	@Deprecated
-	public String getMethodValue() {
-		return this.httpMethod.name();
-	}
-
 	@Override
 	public URI getURI() {
 		return this.url;