chore: optimize outline treeview perf

[Aaaaash]

变动类型

• 代码风格优化

需求背景和解决方案

没有图，原理和之前几个一样

changelog

• 优化大纲面板 treeview 渲染性能

[codecov-commenter]

Codecov Report

Merging #176 (e4177d8) into main (78ee9a6) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #176      +/-   ##
==========================================
- Coverage   59.40%   59.40%   -0.01%     
==========================================
  Files        1180     1180              
  Lines       72354    72354              
  Branches    14978    14978              
==========================================
- Hits        42983    42979       -4     
- Misses      26768    26771       +3     
- Partials     2603     2604       +1     

Impacted Files	Coverage Δ
packages/monaco/src/browser/schema-registry.ts	68.88% <0.00%> (-2.23%)	⬇️
...erences/src/browser/preference-settings.service.ts	79.16% <0.00%> (-0.70%)	⬇️
...kages/theme/src/browser/workbench.theme.service.ts	71.77% <0.00%> (-0.61%)	⬇️

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[erha19]

LGTM