fix(query-builder): Fix for comments

- Remove qb overriders from igx-dialog theme,
- Remove unused variables related to the qb from igx-grid theme

Author: desig9stein

projects/igniteui-angular/src/lib/core/styles/components/dialog/_dialog-theme.scss

@@ -117,20 +117,6 @@
 
     %igx-dialog-display {
         outline-style: none;
-
-        %advanced-filter {
-            box-shadow: none;
-            border: none;
-        }
-
-        %query-level-0 {
-            padding: 0;
-        }
-
-        %advanced-filter__header {
-            padding-block-start: 0;
-            padding-inline: 0;
-        }
     }
 
     %igx-dialog--hidden {

projects/igniteui-angular/src/lib/core/styles/components/grid/_grid-theme.scss

@@ -3215,11 +3215,6 @@
         }
 
         igx-query-builder {
-            //--igx-query-builder-background: #{var-get($theme, 'filtering-row-background')};
-            //--igx-query-builder-background-and: #{var-get($theme, 'filtering-background-and')};
-            //--igx-query-builder-background-and--focus: #{var-get($theme, 'filtering-background-and--focus')};
-            //--igx-query-builder-background-or: #{var-get($theme, 'filtering-background-or')};
-            //--igx-query-builder-background-or--focus: #{var-get($theme, 'filtering-background-or--focus')};
             box-shadow: none;
             border: none;
             border-radius: inherit;