Fix navigation opened section spacing (#22222)

## Summary

- Remove the collapsed empty `Opened` sidebar section when no opened
object exists.
- Restore the first navigation section top alignment with the settings
`User` section.

## Before/After

Visual verification after the fix: in the current fixture data, the
first visible main sidebar section (`Favorites`) starts at y=92,
matching the settings `User` section at y=92. This confirms there is no
collapsed `Opened` spacer pushing the main drawer content down.

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packages/twenty-front/src/modules/navigation-menu-item/display/sections/components/NavigationDrawerOpenedSection.tsx

@@ -17,15 +17,15 @@ export const NavigationDrawerOpenedSection = () => {
     (item) => item.id === objectMetadataIdForOpenedSection,
   );
 
-  const shouldShowOpenedSection = isDefined(objectMetadataItem);
+  if (!isDefined(objectMetadataItem)) {
+    return null;
+  }
 
   return (
-    <AnimatedExpandableContainer isExpanded={shouldShowOpenedSection}>
+    <AnimatedExpandableContainer isExpanded>
       <NavigationDrawerSectionForObjectMetadataItems
         sectionTitle={t`Opened`}
-        objectMetadataItems={
-          isDefined(objectMetadataItem) ? [objectMetadataItem] : []
-        }
+        objectMetadataItems={[objectMetadataItem]}
       />
     </AnimatedExpandableContainer>
   );