Add the necessary hints for use of Cglib proxies

This commit expands GeneratedClassHandler to allow invocation of
declared fields and methods. Generated proxies have a number of
internal fields and methods that are invoked via reflection.

See gh-28954

spring-context/src/test/java/org/springframework/context/aot/GeneratedClassHandlerTests.java

@@ -54,7 +54,8 @@ class GeneratedClassHandlerTests {
 		String className = "com.example.Test$$Proxy$$1";
 		this.handler.accept(className, TEST_CONTENT);
 		assertThat(RuntimeHintsPredicates.reflection().onType(TypeReference.of(className))
-				.withMemberCategory(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS))
+				.withMemberCategories(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+						MemberCategory.INVOKE_DECLARED_METHODS, MemberCategory.DECLARED_FIELDS))
 				.accepts(this.generationContext.getRuntimeHints());
 	}