fix(grid): fix build error

Author: desig9stein

projects/igniteui-angular/src/lib/core/styles/themes/schemas/dark/_grid.scss

@@ -189,7 +189,7 @@ $dark-fluent-grid: extend(
 
         row-selected-hover-text-color: (
             igx-contrast-color: ('grays', 200),
-        ),summary
+        ),
 
         cell-selected-within-background: (
             igx-color: ('grays', 100),