Aligned the two navs horizontally

## What does this MR do?

Previously the 2 top navs were not aligned horizontally together. The top nav would be slightly to the left due to the settings dropdown. This corrects that by putting `position: absolute` on the dropdown toggle.

## What are the relevant issue numbers?

Closes #18513 

## Screenshots (if relevant)

![Screen_Shot_2016-06-13_at_10.20.22](/uploads/46f39a84dde74707578970f70ddda511/Screen_Shot_2016-06-13_at_10.20.22.png)

See merge request !4616