Remove outdated Session's Cookie override

Closes gh-45523

Author: snicoll

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/server/Session.java

@@ -24,6 +24,7 @@
 import org.springframework.boot.context.properties.ConfigurationPropertiesSource;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 import org.springframework.boot.convert.DurationUnit;
+import org.springframework.boot.web.server.Cookie;
 
 /**
  * Session properties.
@@ -113,15 +114,6 @@ SessionStoreDirectory getSessionStoreDirectory() {
 		return this.sessionStoreDirectory;
 	}
 
-	/**
-	 * Session cookie properties. This class is provided only for back-compatibility
-	 * reasons, consider using {@link org.springframework.boot.web.server.Cookie} whenever
-	 * possible.
-	 */
-	public static class Cookie extends org.springframework.boot.web.server.Cookie {
-
-	}
-
 	/**
 	 * Available session tracking modes (mirrors
 	 * {@link jakarta.servlet.SessionTrackingMode}).