Allow clicking on the down arrow of select boxes

Closes #57

- Adds `pointer-events: none;` to the down arrow of select boxes

core/client/assets/sass/layouts/post-settings-menu.scss

@@ -104,6 +104,7 @@
             @include position(absolute, 50% 0.8em null null);
             position: absolute;
             margin-top: -(0.85em / 2);
+            pointer-events: none;
         };
 
         select {

core/client/assets/sass/modules/forms.scss

@@ -403,6 +403,7 @@ input[type='radio'] {
         @include position(absolute, 50% 0.8em null null);
         position: absolute;
         margin-top: -0.5em;
+        pointer-events: none;
     };
 
     select {