Include landing pages sidebar in sidebar styles of blocks/menus

Summary

In the current styles of blocks in sidebars, the landing pages sidebars are not included and as a result the styles are not applied (Eg. when placing a menu to a Landing Page sidebar).

Steps to reproduce

1. Create a Landing Page
2. Place a menu/block in a section sidebar

Possible fixes

Append the classes of Landing Page to block styles in blocks.scss