sticky header container created changing header layouts and adding new sections

[timelsass]

The sticky header container gets created when theme_mods are being updated, and the styling can throw off the layout of header on the left and header on the right.

To Reproduce
Steps to reproduce the behavior:

1. Go to customizer ▸ Design ▸ Header ▸Layout
2. Select "Left" for Header Position option.
3. Press "+ Add Section" for the Header Layout to add a new empty section.

The result is that there is an empty sticky-header container, which takes up the space of the standard header.

Expected behavior
The sticky header container needs to be hidden when the fixed position header is set to false.

Screenshots