fix(navbar): icon colors in AppBuilder (#13730)

Author: SisIvanova

projects/igniteui-angular/src/lib/core/styles/components/navbar/_navbar-theme.scss

@@ -119,7 +119,7 @@
         flex-grow: 1;
         user-select: text;
         display: flex;
-        flex-direction: row
+        flex-direction: row;
     }
 
     %igx-navbar-bundle {
@@ -131,8 +131,9 @@
         }
     }
 
-    %igx-navbar-icon-display {
-        > igx-icon,
+    %igx-navbar-icon-display,
+    %igx-navbar-part {
+        igx-icon,
         [igxButton='icon'] {
             --component-size: 3;