fix(button): Use correct padding for Text Button

According to the [M3 spec](https://m3.material.io/components/buttons/specs#899b9107-0127-4a01-8f4c-87f19323a1b4), Text Buttons have less side padding than the other Button variants.

PiperOrigin-RevId: 463712391

button/lib/_text-button-theme.scss

@@ -26,12 +26,12 @@ $light-theme: tokens.md-comp-text-button-values();
 @mixin theme-styles($theme, $resolvers: resolvers.$material) {
   $theme: theme.validate-theme-styles($light-theme, $theme);
   // TODO(b/198759625): Remove once spacing tokens are formally added
-  $theme: map.set($theme, 'spacing-leading', 24px);
-  $theme: map.set($theme, 'spacing-trailing', 24px);
-  $theme: map.set($theme, 'with-icon-spacing-leading', 16px);
-  $theme: map.set($theme, 'with-icon-spacing-trailing', 24px);
-  $theme: map.set($theme, 'with-trailing-icon-spacing-leading', 24px);
-  $theme: map.set($theme, 'with-trailing-icon-spacing-trailing', 16px);
+  $theme: map.set($theme, 'spacing-leading', 12px);
+  $theme: map.set($theme, 'spacing-trailing', 12px);
+  $theme: map.set($theme, 'with-icon-spacing-leading', 12px);
+  $theme: map.set($theme, 'with-icon-spacing-trailing', 16px);
+  $theme: map.set($theme, 'with-trailing-icon-spacing-leading', 16px);
+  $theme: map.set($theme, 'with-trailing-icon-spacing-trailing', 12px);
   $theme: _resolve-theme($theme, $resolvers);
   $theme: theme.create-theme-vars($theme, $_custom-property-prefix);