fix: DropDownItem prop-types active prop (fix: #3598)

[mxschmitt]

Fixes #3598.

I hope it's okay, that I simplified these == null and != null statements. (active var type is null|bool and makeEventKey() is null|String)

[taion]

i don't think this is quite right... we want to treat false differently from null here

[taion]

this looks good

the one thing i might do naming-wise is – do active: propsActive in destructuring, then call the calculated value active

but that's super nit-picky

[taion]

should we disable the "automatically dismiss reviews" thing? assuming that was an automatic dismissal