fix(material/radio): Apply tokens at mixin root (#27864)

Applies radio tokens at the theme mixin's root selector (or html if the mixin
is called with no selector). This makes it easier for users to override tokens
without worrying about specificity.

Author: mmalerba

src/material/list/_list-theme.scss

@@ -83,6 +83,11 @@
     @include mdc-list-theme.theme($mdc-list-density-tokens);
   }
 
+  .mdc-list-item__start,
+  .mdc-list-item__end {
+    @include mdc-radio-theme.theme(tokens-mdc-radio.get-density-tokens($theme));
+  }
+
   // TODO(mmalerba): This is added to maintain the same style MDC used prior to the token-based API,
   //  to avoid screenshot diffs. We should remove it in favor of following MDC's current style, or
   //  add custom tokens for it.

src/material/radio/_radio-theme.scss

@@ -1,7 +1,7 @@
-@use '@material/radio/radio' as mdc-radio;
 @use '@material/radio/radio-theme' as mdc-radio-theme;
 @use '@material/form-field' as mdc-form-field;
 @use '../core/mdc-helpers/mdc-helpers';
+@use '../core/style/sass-utils';
 @use '../core/theming/theming';
 @use '../core/theming/inspection';
 @use '../core/tokens/token-utils';
@@ -10,7 +10,7 @@
 @use '../core/tokens/m2/mat/radio' as tokens-mat-radio;
 
 @mixin base($theme) {
-  .mat-mdc-radio-button {
+  @include sass-utils.current-selector-or-root() {
     @include mdc-radio-theme.theme(tokens-mdc-radio.get-unthemable-tokens());
     @include token-utils.create-token-values(
         tokens-mat-radio.$prefix, tokens-mat-radio.get-unthemable-tokens());
@@ -46,8 +46,11 @@
 }
 
 @mixin typography($theme) {
-  .mat-mdc-radio-button {
+  @include sass-utils.current-selector-or-root() {
     @include mdc-radio-theme.theme(tokens-mdc-radio.get-typography-tokens($theme));
+  }
+
+  .mat-mdc-radio-button {
     @include mdc-helpers.using-mdc-typography($theme) {
       @include mdc-form-field.core-styles($query: mdc-helpers.$mdc-typography-styles-query);
     }
@@ -57,7 +60,7 @@
 @mixin density($theme) {
   $density-scale: inspection.get-theme-density($theme);
 
-  .mat-mdc-radio-button .mdc-radio {
+  @include sass-utils.current-selector-or-root() {
     @include mdc-radio-theme.theme(tokens-mdc-radio.get-density-tokens($theme));
   }