fix(material-experimental/mdc-menu): Use body1 typography for menu co…

…ntent (#23657)

We already fixed this for menu items, but MDC also sets the wrong
typograph level on the menu content element, which can bleed through
into people's custom menu content.

(cherry picked from commit 3181780)

src/material-experimental/mdc-menu/_menu-theme.scss

@@ -57,6 +57,7 @@
 
       // MDC uses the `subtitle1` level for list items, but the spec shows `body1` as the correct
       // level.
+      &,
       .mat-mdc-menu-item .mdc-list-item__primary-text {
         @include mdc-typography.typography(body1, $query: mdc-helpers.$mat-typography-styles-query);
       }