[FIX] website: fix popup height

- The modal content of the popup snippet had a maximum height of 100%
because of a global rule on modals. But, here, the scrollable element
is not the modal so we dont want this rule.

- For the popup to be scrolled correctly we also had to remove the
rule that adds a fixed 100% height on modal-dialog and we added a
min-height of 100% to correctly display the popup in the middle
position.

Part of https://github.com/odoo/odoo/pull/61998
task-2312878

addons/website/static/src/snippets/s_popup/001.scss

 .s_popup[data-vcss='001']  {
     .modal-content {
         min-height: $font-size-lg * 2;
+        max-height: none;
         border: 0;
         border-radius: 0;
         box-shadow: $modal-content-box-shadow-sm-up;
     }
 
+    .modal-dialog {
+        height: auto;
+        min-height: 100%;
+    }
+
     // Close icon
     .s_popup_close {
         z-index: $zindex-modal;