fix(material/radio): allow touch target size to be customized

Adds a token that allows for the radio button touch target to be customized.

Author: crisbeto

src/material/radio/_m2-radio.scss

@@ -15,6 +15,7 @@
       // determines the size of the radio button itself and there are internal
       // tests who don't configure the theme correctly.
       radio-state-layer-size: 40px,
+      radio-touch-target-size: 48px,
     ),
     color: private-get-color-palette-color-tokens($theme, secondary),
     typography: (

src/material/radio/_m3-radio.scss

@@ -16,6 +16,7 @@
     base: (
       radio-disabled-unselected-icon-opacity: 0.38,
       radio-disabled-selected-icon-opacity: 0.38,
+      radio-touch-target-size: 48px,
     ),
     color: (
       radio-checked-ripple-color: map.get($system, primary),

src/material/radio/radio.scss

@@ -88,8 +88,8 @@ $fallbacks: m3-radio.get-tokens();
   position: absolute;
   top: 50%;
   left: 50%;
-  height: 48px;
-  width: 48px;
+  height: token-utils.slot(radio-touch-target-size, $fallbacks);
+  width: token-utils.slot(radio-touch-target-size, $fallbacks);
   transform: translate(-50%, -50%);
   display: token-utils.slot(radio-touch-target-display, $fallbacks);