Remove styles that add unnecessary border around collapsed facets.

We often override this to remove these styles:
https://github.com/sul-dlss/stanford-arclight/blob/a323e8108d14a9876873705ccd53a68db03c7b69/app/assets/stylesheets/sulCollection.scss#L227-L229

It would be better not to have them and let people add them if necessary.

app/assets/stylesheets/blacklight/_facets.scss

@@ -3,13 +3,18 @@
   --bl-facet-active-item-color: #{$facet-active-item-color};
   --bl-facet-remove-color: var(--bs-secondary-color);
 
-  --bl-facets-smallish-padding: 0.25rem;
-  --bl-facets-smallish-border: var(--bs-border-width) solid
-    var(--bs-border-color);
-  --bl-facets-smallish-margin-bottom: #{$spacer};
-  --bl-facets-smallish-border-radius: #{$border-radius};
-
   .facet-toggle-button {
+    --bs-navbar-toggler-padding-x: #{$navbar-toggler-padding-x};
+    --bs-navbar-toggler-padding-y: #{$navbar-toggler-padding-y};
+    --bs-navbar-toggler-border-color: #{$navbar-light-toggler-border-color};
+    --bs-navbar-toggler-border-radius: #{$navbar-toggler-border-radius};
+    color: $navbar-light-active-color;
+
+    &:hover,
+    &:focus {
+      color: $navbar-light-active-color;
+    }
+
     [data-hide-label] {
       display: inline;
     }
@@ -28,13 +33,6 @@
   }
 }
 
-.facets-toggleable-md {
-  border: var(--bl-facets-smallish-border);
-  padding: var(--bl-facets-smallish-padding);
-  margin-bottom: var(--bl-facets-smallish-margin-bottom);
-  border-radius: var(--bl-facets-smallish-border-radius);
-}
-
 .no-js {
   @include media-breakpoint-down(lg) {
     #sidebar {