[Bug]全屏按钮设置不生效

[skeetyu]

Checklist

• I am using LTS version of Node.js.
• I am using the latest v2 version of VuePress and VuePress official plugins.
• I am using the latest v2 version of vuepress-theme-hope and all plugins in this repo.
• I followed the docs and I double checked my configuration.
• I have searched FAQ and I did not find the answer.

Package name

vuepress-theme-hope

Which operating system are you using?

• macOS
• Windows
• Linux

Describe the bug

开发时在hopeTheme中设置fullscreen为true，但是在navbar中就是不显示全屏按钮，在Microsoft Edge和Safari试了都不行。（设置其它属性比如print:false什么都能生效）

Additional context

No response

[github-actions]

Hello @skeetyu. Please provide a minimal reproduction using a GitHub repository or vuepress-theme-hope.github.io/v2-new. Issues marked with needs reproduction will be closed if they have no activity within 3 days.