fix(button): Fix n-button's style is overwritten when using other style library

[XieZongChen]

close #1808

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/tusimple/naive-ui/EMkwthHCeQwjyzSxS8NjC3rDFYcH
✅ Preview: https://naive-ui-git-fork-amadeus711-fix-nbutton-color-8f185c-tusimple.vercel.app

[codecov]

Codecov Report

Merging #1820 (7396a6c) into main (664a08d) will decrease coverage by 0.01%.
The diff coverage is 23.52%.

❗ Current head 7396a6c differs from pull request most recent head da957f0. Consider uploading reports for the commit da957f0 to get more accurate results

@@            Coverage Diff             @@
##             main    #1820      +/-   ##
==========================================
- Coverage   64.80%   64.79%   -0.02%     
==========================================
  Files         890      890              
  Lines       17302    17297       -5     
  Branches     4100     4098       -2     
==========================================
- Hits        11213    11208       -5     
+ Misses       5314     5313       -1     
- Partials      775      776       +1     

Impacted Files	Coverage Δ
src/button/src/styles/button.cssr.ts	80.00% <ø> (ø)
src/button/src/Button.tsx	64.86% <23.52%> (ø)
src/popselect/src/PopselectPanel.tsx	31.57% <0.00%> (-2.85%)	⬇️
src/cascader/src/Cascader.tsx	39.20% <0.00%> (-0.12%)	⬇️
src/cascader/styles/dark.ts	100.00% <0.00%> (ø)
src/cascader/styles/light.ts	100.00% <0.00%> (ø)
src/popselect/src/Popselect.tsx	90.00% <0.00%> (ø)
src/cascader/src/CascaderMenu.tsx	54.54% <0.00%> (ø)
src/_internal/selection/src/Selection.tsx	41.46% <0.00%> (ø)
src/_internal/selection/src/styles/index.cssr.ts	100.00% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0989eee...da957f0. Read the comment docs.