Remove obsolete code

The hasNullableAnnotation() method was made obsolete in commit
b5d153febf.

See gh-34952
See gh-34261

spring-beans/src/main/java/org/springframework/beans/factory/config/DependencyDescriptor.java

@@ -19,7 +19,6 @@ package org.springframework.beans.factory.config;
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.Serializable;
-import java.lang.annotation.Annotation;
 import java.lang.reflect.Field;
 import java.util.Map;
 import java.util.Optional;
@@ -167,20 +166,6 @@ public class DependencyDescriptor extends InjectionPoint implements Serializable
 		}
 	}
 
-	/**
-	 * Check whether the underlying field is annotated with any variant of a
-	 * {@code Nullable} annotation, for example, {@code jakarta.annotation.Nullable} or
-	 * {@code edu.umd.cs.findbugs.annotations.Nullable}.
-	 */
-	private boolean hasNullableAnnotation() {
-		for (Annotation ann : getAnnotations()) {
-			if ("Nullable".equals(ann.annotationType().getSimpleName())) {
-				return true;
-			}
-		}
-		return false;
-	}
-
 	/**
 	 * Return whether this dependency is 'eager' in the sense of
 	 * eagerly resolving potential target beans for type matching.