Add placeholder to signinup modal's secondary logo (#12079)

closes https://github.com/twentyhq/core-team-issues/issues/972

checks - 

- [x]  If we have an icon it should be displayed as `secondary`

<img width="1064" alt="Screenshot 2025-05-16 at 00 33 42"
src="https://github.com/user-attachments/assets/20716df3-28be-40c5-b0fc-2133fccdad83"
/>

- [x] If no icon is provided, display a placeholder

<img width="1062" alt="Screenshot 2025-05-16 at 00 33 09"
src="https://github.com/user-attachments/assets/0241dafe-3d31-4f8e-a9e4-321634f6d41c"
/>

- [x] Add story for auth logos
<img width="550" alt="Screenshot 2025-05-16 at 16 16 24"
src="https://github.com/user-attachments/assets/3859547d-32c5-469f-879b-a130a36a23fa"
/>

<img width="548" alt="Screenshot 2025-05-16 at 16 16 30"
src="https://github.com/user-attachments/assets/4937fa6a-459a-4c75-86ae-2080b1c8a5ae"
/>

<img width="487" alt="Screenshot 2025-05-16 at 16 16 16"
src="https://github.com/user-attachments/assets/2c634be1-4a51-4b06-a590-cdd7eff91b76"
/>

<img width="556" alt="Screenshot 2025-05-16 at 16 16 07"
src="https://github.com/user-attachments/assets/e4a518b4-c338-45c1-a329-5c9f85319c52"
/>

packages/twenty-front/src/pages/auth/PasswordReset.tsx

@@ -173,7 +173,10 @@ export const PasswordReset = () => {
       <Modal.Content isVerticalCentered isHorizontalCentered>
         <StyledMainContainer>
           <AnimatedEaseIn>
-            <Logo secondaryLogo={workspacePublicData?.logo} />
+            <Logo
+              secondaryLogo={workspacePublicData?.logo}
+              placeholder={workspacePublicData?.displayName}
+            />
           </AnimatedEaseIn>
           <Title animate>
             <Trans>Reset Password</Trans>

packages/twenty-front/src/pages/auth/SignInUp.tsx

@@ -41,7 +41,10 @@ const StandardContent = ({
   return (
     <Modal.Content isVerticalCentered isHorizontalCentered>
       <AnimatedEaseIn>
-        <Logo secondaryLogo={workspacePublicData?.logo} />
+        <Logo
+          secondaryLogo={workspacePublicData?.logo}
+          placeholder={workspacePublicData?.displayName}
+        />
       </AnimatedEaseIn>
       <Title animate>{title}</Title>
       {signInUpForm}