Updated tri-layout sidebars to not be cut-off by padding

Would cause effect where scroll area would be cut of by spacing which
looked a bit strange. This retains the same padding sizes but cuts the
content at the header or top of viewport.

resources/sass/_layout.scss

@@ -295,9 +295,9 @@ body.flexbox {
 }
 @include larger-than($xxl) {
   .tri-layout-left-contents, .tri-layout-right-contents {
-    padding: $-m;
+    padding: $-xl $-m;
     position: sticky;
-    top: $-m;
+    top: 0;
     max-height: 100vh;
     min-height: 50vh;
     overflow-y: scroll;