fix: Poor contrast on SlashMenu (#5342)

fixes
[#5304](#5304 (comment))

dark mode
<img width="1425" alt="Screenshot 2024-05-09 at 1 59 56 AM"
src="https://github.com/twentyhq/twenty/assets/60315832/70230f9e-607a-462a-8823-db8350d86bc4">


<br>
<br>
Light mode
<img width="1448" alt="Screenshot 2024-05-09 at 2 01 06 AM"
src="https://github.com/twentyhq/twenty/assets/60315832/523488a5-21de-4911-b11b-e28fba9adae6">

Co-authored-by: Lucas Bordeau <bordeau.lucas@gmail.com>

packages/twenty-front/src/modules/ui/layout/dropdown/components/DropdownMenu.tsx

@@ -8,10 +8,12 @@ const StyledDropdownMenu = styled.div<{
   backdrop-filter: ${({ theme, disableBlur }) =>
     disableBlur ? 'none' : theme.blur.medium};
 
+  color: ${({ theme }) => theme.font.color.secondary};
+
   background: ${({ theme, disableBlur }) =>
     disableBlur
       ? theme.background.primary
-      : theme.background.transparent.secondary};
+      : theme.background.transparent.primary};
 
   border: ${({ disableBorder, theme }) =>
     disableBorder ? 'none' : `1px solid ${theme.border.color.medium}`};