Bug: Footer button gets pushed upwards even though no bottom menu bar is present

[abias]

Steps to reproduce:

• Go to Site administration -> Appearance -> Boost Union -> Content -> Footer
• Set theme_boost_union | enablefooterbutton = Enable on Desktop, Tablet and Mobile
• Go to Site administration -> Appearance -> Boost Union -> Smart menus
• Create an arbitrary smart menu in the main navigation
• Resize your browser width

Expected result:

• On larger screens, the footer button is presented just above the bottom fold
• On smaller screens, the footer button is presented just above the bottom fold as well

Actual result:

• On larger screens, the footer button is presented just above the bottom fold which is fine
• On smaller screens, the footer button is pushed upwards unnecessarily

Countercheck 1:

• Go to Site administration -> Appearance -> Boost Union -> Smart menus
• Disable the smart menu
• Do the test again and you will see that the footer button stays at the bottom fold

Countercheck 2:

• Go to Site administration -> Appearance -> Boost Union -> Smart menus
• Re-enable the smart menu
• Re-configure the smart menu to be shown in the bottom bar instead of the main navigation
• Do the test again and you will see that the footer button is now pushed upwards as the bottom bar is now shown