Remove blank space after footer

In commit a8537f7e1 we added a `height: 100%` rule on links inside
cards, which is great for cards in the "Featured" section of the
homepage. However, the card in the "Open processes" section of the
homepage has as many links inside as open processes, causing its height
to be 300% if there are three processes and so expanding below the
footer.

app/assets/stylesheets/layout.scss

@@ -2820,6 +2820,10 @@ table {
   .cards-container {
     display: flex;
     flex-wrap: wrap;
+
+    .card a {
+      height: 100%;
+    }
   }
 
   .card {
@@ -2828,8 +2832,6 @@ table {
     overflow: visible;
 
     a {
-      height: 100%;
-
       img {
         transition-duration: 0.3s;
         transition-property: transform;