✨ [Feature]: bubble 主题支持

[zzxming]

What problem does this feature solve

目前样式仅包括了 snow 主题，quill 本身支持两种主题模式，希望能与 quill 一致

What does the proposed API look like

const fluentEditor = new FluentEditor('#editor', {
  theme: 'bubble',
});

What is your project name

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