bug(mat-navigation-list): Navigation List active items should have on-secondary-container color

### Description

Currently, Navigation List active item has a secondary-container background, but does not use on-secondary-container color, which we find erroneous

### Reproduction

https://material.angular.dev/components/list/examples#list-navigation

### Expected Behavior

Navigation List active items should have color of on-secondary-container, since they have a background color of secondary-container

### Actual Behavior

Navigation List items do not update their color when set to active and remain on-surface even though their background is no longer surface

### Environment

- Angular: v21
- CDK/Material: v21
- Browser(s): any
- Operating System (e.g. Windows, macOS, Ubuntu): any

打开 material.angular.dev/components/list/examples#list-navigation 中的 Navigation List 示例，并检查活动项的样式。完成标准是活动项保留其 secondary-container 背景，并使用 on-secondary-container 颜色而不是 on-surface；更改后验证示例的行为。

由索引模型根据 Issue 内容生成。