Replace legacy $spacing-X vars with Compound Design Tokens (#34380)

* Replace legacy `$spacing-X` vars with Compound Design Tokens

* Remove unused font size vars

* Use calc to get negative spacing vars

apps/web/res/css/views/messages/_MPollBody.pcss

@@ -47,7 +47,7 @@ $poll-max-width: 550px;
 
         .mx_Spinner {
             flex: 0;
-            margin-left: $spacing-8;
+            margin-left: var(--cpd-space-2x);
         }
     }
 }
@@ -59,7 +59,7 @@ $poll-max-width: 550px;
 
 .mx_MPollBody_allOptions {
     display: grid;
-    gap: $spacing-16;
-    margin-bottom: $spacing-8;
+    gap: var(--cpd-space-4x);
+    margin-bottom: var(--cpd-space-2x);
     max-width: $poll-max-width;
 }