MAGETWO-92071: Build stabilization

Remove unused variables

Author: danmooney2

app/code/Magento/PageBuilder/view/adminhtml/web/css/source/_var.less

@@ -34,10 +34,6 @@
 @color-pagebuilder-darker-gray: #2b2625;
 @color-pagebuilder-darkest-gray: #1c1918;
 @color-pagebuilder-light-blue: #bfe2f0;
-@color-red: #f00;
-@color-warm-blue: #529cdb;
-@color-pinkish-beige: #ffe6dd;
-@color-concrete: #e6f0f4;
 
 //
 //  Fonts