[FIX] website: fix showcase snippet images stretched

Before this commit, if we replaced an icon of the showcase snippet
with an image, this image was streched depending on title size (if too
long and on 2 lines). Its because the align-self default value of a
flex item is strech.

task-2447087

closes odoo/odoo#67234

Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>

addons/website/static/src/scss/website.scss

@@ -1411,3 +1411,12 @@ $ribbon-padding: 100px;
         display: none;
     }
 }
+
+// Snippet Showcase
+.s_showcase_icon {
+    // Avoid images stretched depending on title size (when icons
+    // are images an not Font Awesome icons). Because the default
+    // value of "align-self" is "strech". We put this code here to
+    // avoid having to create a new scss file in a stable version.
+    align-self: flex-start;
+}