fix: the style of the context menu of ActivityBarItem

[kiwiwong]

Description

Fix the style of the context menu of ActivityBarItem.

Fixes #577

Changes

• Replace DropDown with contextView to display ActivityBarItem's context menu.

[codecov]

Codecov Report

Merging #613 (53dd7b2) into main (b11b4e9) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #613      +/-   ##
==========================================
+ Coverage   87.28%   87.32%   +0.03%     
==========================================
  Files         190      190              
  Lines        5578     5577       -1     
  Branches     1243     1241       -2     
==========================================
+ Hits         4869     4870       +1     
+ Misses        699      697       -2     
  Partials       10       10              

Impacted Files	Coverage Δ
src/workbench/activityBar/activityBarItem.tsx	100.00% <100.00%> (ø)
src/common/dom.ts	83.58% <0.00%> (+2.98%)	⬆️

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[wewoor]

这个修改有测试 Storybook 里面的场景吗？

[wewoor]

+1