Implement new version of the side panel sub header (#16683)

## Before
<img width="822" height="302" alt="CleanShot 2025-12-18 at 17 08 09@2x"
src="https://github.com/user-attachments/assets/d4d0f783-64f2-4164-9a4d-42c341fa828d"
/>

## After
<img width="836" height="370" alt="CleanShot 2025-12-18 at 17 07 49@2x"
src="https://github.com/user-attachments/assets/aca7a72f-bb83-4e40-89d2-f62bb7c8f053"
/>

packages/twenty-front/src/modules/command-menu/components/CommandMenuBackButton.tsx

@@ -13,11 +13,13 @@ import { MenuItem } from 'twenty-ui/navigation';
 
 const StyledNavigationIcon = styled.div`
   align-items: center;
-  color: ${({ theme }) => theme.font.color.secondary};
   cursor: pointer;
   display: flex;
   justify-content: center;
-  margin-right: ${({ theme }) => theme.spacing(1)};
+`;
+
+const StyledIconChevronLeft = styled(IconChevronLeft)`
+  color: ${({ theme }) => theme.font.color.secondary};
 `;
 
 export const CommandMenuBackButton = () => {
@@ -50,7 +52,7 @@ export const CommandMenuBackButton = () => {
       clickableComponent={
         <StyledNavigationIcon onContextMenu={handleBackButtonContextMenu}>
           <IconButton
-            Icon={IconChevronLeft}
+            Icon={StyledIconChevronLeft}
             size="small"
             variant="tertiary"
             onClick={goBackFromCommandMenu}