fix: only add default color once

[pipiiiiii]

Types

• 🐛 Bug Fixes

Background or solution

🤖 Generated by Copilot at 588e562

• Fix a bug that caused wrong token colors in monaco editor by checking for the scope property of the theme settings (link)
• Add a scope property with an empty array to the default theme settings object to match the expected format for the fillDefaults function (link)

Issue: #2686

每次初始化 theme 时，会修改 themeSetting引用，导致 https://github.com/opensumi/core/blob/main/packages/theme/src/browser/theme-data.ts#L576
这里 index 会不一致，每次颜色会错位一个
有因为scope 会被补充为 ['']，所以初始化的判断逻辑改一下就可以了

Changelog

🤖 Generated by Copilot at 588e562

Fixed a bug in the workbench theme service that affected the monaco editor. Improved the default theme settings with a scope property.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (e2270b4) 57.72% compared to head (41492b7) 57.72%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2753   +/-   ##
=======================================
  Coverage   57.72%   57.72%           
=======================================
  Files        1327     1327           
  Lines       83581    83587    +6     
  Branches    17378    17381    +3     
=======================================
+ Hits        48246    48253    +7     
+ Misses      32114    32113    -1     
  Partials     3221     3221           

Flag	Coverage Δ
jsdom	52.72% <100.00%> (+<0.01%)	⬆️
node	16.79% <0.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...kages/theme/src/browser/workbench.theme.service.ts	71.50% <100.00%> (ø)

... and 6 files with indirect coverage changes

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[opensumi]

ChatGPT Code Review:

1. 建议修改代码中的注释，将英文的字符改为中文的字符
2. 建议在条件语句中使用全等号（===）代替双等号（==）以避免类型转换错误。
3. 修复了一个导致 monaco 编辑器中颜色不准确的错误，解决方案是检查主题设置对象的 scope 属性，并使用 fillDefaults 函数向默认主题设置对象添加 scope 属性。这个修复同样解决了每次切换主题时导致颜色错位的 bug。