refactor(Coupon): simplify the checkbox usage

[chenjiahan]

Simplify the checkbox usage and fix some mistakes.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 54.54545% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 89.76%. Comparing base (3a524e8) to head (dda84bd).

Files	Patch %	Lines
packages/vant/src/coupon-list/CouponList.tsx	25.00%	5 Missing and 1 partial ⚠️
packages/vant/src/coupon-cell/CouponCell.tsx	71.42%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12771      +/-   ##
==========================================
+ Coverage   89.68%   89.76%   +0.07%     
==========================================
  Files         257      257              
  Lines        6884     6875       -9     
  Branches     1674     1672       -2     
==========================================
- Hits         6174     6171       -3     
+ Misses        382      376       -6     
  Partials      328      328              

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