Remove TODO comments about spacing variables (#10695)

The variables on _spacing.pcss have been deprecated by https://github.com/matrix-org/matrix-react-sdk/pull/10686

res/css/views/settings/_FontScalingPanel.pcss

@@ -24,11 +24,11 @@ limitations under the License.
     display: flow-root;
 
     &.mx_IRCLayout {
-        padding-top: 9px; /* TODO: Use a spacing variable */
+        padding-top: 9px;
     }
 
     .mx_EventTile[data-layout="bubble"] {
-        margin-top: 30px; /* TODO: Use a spacing variable */
+        margin-top: 30px;
     }
 
     .mx_EventTile_msgOption {
@@ -39,7 +39,7 @@ limitations under the License.
 .mx_FontScalingPanel_fontSlider {
     display: flex;
     align-items: center;
-    padding: 15px $spacing-20 35px; /* TODO: Use spacing variables */
+    padding: 15px $spacing-20 35px;
     background: rgba($quinary-content, 0.2);
     border-radius: 10px;
     font-size: $font-10px;