improvement(tabs): Fix tab indicator precedence issue & icon size css values are applied to icon

PiperOrigin-RevId: 482190989

Author: material-web-copybara

packages/mdc-tab/_tab-theme.scss

@@ -256,6 +256,8 @@ $custom-property-prefix: 'tab';
   @include _divider-color(map.get($theme, divider-color));
   @include _divider-height(map.get($theme, divider-height));
 
+  @include _icon-size(map.get($theme, with-icon-icon-size));
+
   @include _active-icon-color(
     (
       default: map.get($theme, with-icon-active-icon-color),
@@ -543,9 +545,11 @@ $custom-property-prefix: 'tab';
 }
 
 @mixin _icon-size($size) {
-  @include theme.property('width', $size);
-  @include theme.property('height', $size);
-  @include theme.property('font-size', $size);
+  .mdc-tab__icon {
+    @include theme.property('width', $size);
+    @include theme.property('height', $size);
+    @include theme.property('font-size', $size);
+  }
 }
 
 @mixin _label-text-font-family($font-family) {