fix(navbar): update icon button and icon sizes (#16431)

Author: desig9stein

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

@@ -38,6 +38,11 @@
             igx-input-group {
                 --ig-size: 1;
             }
+
+            .igx-icon-button,
+            igc-icon-button {
+                --ig-size: 2;
+            }
         }
 
         @if $variant == 'bootstrap' {
@@ -114,30 +119,27 @@
 
         igx-icon,
         igc-icon {
-            --component-size: 3;
+            --component-size: #{if($variant == 'indigo', 2, 3)};
 
             cursor: pointer;
             user-select: none;
             transition: color .15s $out-quad;
+
+            @if $variant == 'indigo' {
+                width: auto;
+                height: auto;
+                padding: rem(6px);
+            }
         }
 
-        >igx-icon,
-        >igc-icon {
+        > igx-icon,
+        > igc-icon {
             color: var-get($theme, 'idle-icon-color');
 
             &:hover {
                 color: var-get($theme, 'hover-icon-color');
             }
         }
-
-        @if $variant == 'indigo' {
-            igx-icon,
-            igc-icon {
-                --component-size: 2;
-
-                margin-inline: rem(6px);
-            }
-        }
     }
 
     igx-navbar-action,