fix(*): build errors due to displayDensity changes #3310

Author: SAndreeva

projects/igniteui-angular/src/lib/grids/summaries/summary-row.component.ts

@@ -70,15 +70,8 @@ export class IgxSummaryRowComponent implements DoCheck  {
         return this.element.nativeElement;
     }
 
-    // TO DO: to be refactored when displayDensity refactoring is merged
     get gridDensity(): string {
-        if (this.grid.isCosy()) {
-            return DisplayDensity.cosy;
-        } else if (this.grid.isCompact()) {
-            return DisplayDensity.compact;
-        } else {
-            return DisplayDensity.comfortable;
-        }
+        return this.grid.displayDensity || DisplayDensity.comfortable;
     }
 
     public getColumnSummaries(columnName) {