Make buttons full-width in grey-bordered cards (#32231)

GitOrigin-RevId: 0b0f9500d9676a741f31bea8e52a3fd4b2399c2e

services/web/frontend/stylesheets/components/card.scss

@@ -182,6 +182,10 @@
     .card-body {
       padding: var(--spacing-10);
     }
+
+    .btn {
+      width: 100%;
+    }
   }
 
   &.card-green-border {