fix(theme:default): fix inconsistency of top icon size

[cipchk]

• close 顶部菜单折叠开关html标签使用与其他功能按钮不一致，导致图标大小不协调 ng-alain#2519

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/ng-alain/delon/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[cipchk]

Preview is ready!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.87%. Comparing base (811095b) to head (c7cd16c).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #1841    +/-   ##
========================================
  Coverage   94.87%   94.87%            
========================================
  Files         315      315            
  Lines        8931     8931            
  Branches     1800     1699   -101     
========================================
  Hits         8473     8473            
  Misses        382      382            
  Partials       76       76            

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[zengqinglei]

我检查了预览界面，大小仍然不一致；
同时我也查看了你们提交的源码，发现应该是针对这个是无效的，麻烦在确认下：

[cipchk]

针对这个 PR 的预览应该是 https://preview-1841-ng-alain-delon.surge.sh/dev/home

png:

[zengqinglei]

@cipchk
Accepted, thank you!