Fixed dropdown search field height in ie11

## What does this MR do?

Fixes the height of the search input in dropdown menus.

## What are the relevant issue numbers?

Closes #19684 

## Screenshots (if relevant)

![Screen_Shot_2016-07-11_at_11.49.52](/uploads/fc25bc3d2c3bbd195f30d1953dc12662/Screen_Shot_2016-07-11_at_11.49.52.png)

See merge request !5179