Replace SubMenu findDOMNode usage.

[dispalt]

I manually verified this all works with story book. The tests pass, but I am sure it could be more elegant. Let me know if you have feedback. This is the follow up to #362

[codecov]

Codecov Report

Merging #363 (088a662) into master (f9b55d6) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #363      +/-   ##
==========================================
+ Coverage   95.73%   95.76%   +0.02%     
==========================================
  Files          11       11              
  Lines         915      921       +6     
  Branches      270      271       +1     
==========================================
+ Hits          876      882       +6     
  Misses         39       39              

Impacted Files	Coverage Δ
src/MenuItem.tsx	100.00% <ø> (ø)
src/DOMWrap.tsx	83.82% <100.00%> (+0.36%)	⬆️
src/SubMenu.tsx	98.29% <100.00%> (+0.01%)	⬆️
src/SubPopupMenu.tsx	96.42% <100.00%> (+0.02%)	⬆️

---

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 f9b55d6...088a662. Read the comment docs.

[lgtm-com]

This pull request introduces 2 alerts when merging 8b67c98 into f9b55d6 - view on LGTM.com

new alerts:

• 2 for Unused variable, import, function or class

[dispalt]

This pull request introduces 2 alerts when merging 8b67c98 into f9b55d6 - view on LGTM.com

new alerts:

• 2 for Unused variable, import, function or class

Fixed and force-pushed.

[dispalt]

Let me know if you'd like me to change something, @zombieJ . Thanks!

[dispalt]

@zombieJ ping, if you could take a look, I'd be eternally grateful =)

[anuarml]

any update on when this will be merged? it would be great it this issue is closed ant-design/ant-design#26136 , thanks! @zombieJ

[dispalt]

Hey folks, just a friendly ping, would love some feedback or a merge @afc163

[yoyo837]

Please help to check rc-menu@9

[dispalt]

Ill give it go!