Remove position: static from dropdowns in navbar

Created by: mattonit

Is there a reason to use position: static; for dropdowns in navbar? I use code from v4-dev and it works fine, but it causes a problem in your new website

The problem isn't visible in v4-dev because Popper set the position of the dropdown to absolute (as it should be). Previously my PR (#22010) was rejected because you said that was intentional to use position: static, but when currently it's fixed by popper.js

Here's what I'm talking about:

And without position: static;

Isn't that better?

Tested on latest Chrome, Win 7/Win 10/Ubuntu 17.04/OS X Sierra 10.12.5