chore: Update inbox view context menu (#12090)

# Pull Request Template

## Description

This PR updates the inbox view context menu to use the existing
conversation card context menu for consistency.

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

### Screenshots

**Before**
<img width="395" height="257" alt="image"
src="https://github.com/user-attachments/assets/88620d0c-99b4-480d-a9c3-89b78907dfc6"
/>
<img width="395" height="257" alt="image"
src="https://github.com/user-attachments/assets/e42523ba-f880-47c6-b3a0-131ffa41fb1b"
/>


**After**
<img width="395" height="257" alt="image"
src="https://github.com/user-attachments/assets/13cf7528-2c37-4077-9e66-7bd0e53df0d5"
/>
<img width="395" height="257" alt="image"
src="https://github.com/user-attachments/assets/8558f574-ef33-4b58-b0f7-fbddbcefe200"
/>


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Pranav <pranavrajs@gmail.com>

app/javascript/dashboard/components-next/Inbox/InboxCard.vue

@@ -63,11 +63,12 @@ const lastActivityAt = computed(() => {
 });
 
 const menuItems = computed(() => [
-  { key: 'delete', label: t('INBOX.MENU_ITEM.DELETE') },
   {
     key: isUnread.value ? 'mark_as_read' : 'mark_as_unread',
+    icon: isUnread.value ? 'mail' : 'mail-unread',
     label: t(`INBOX.MENU_ITEM.MARK_AS_${isUnread.value ? 'READ' : 'UNREAD'}`),
   },
+  { key: 'delete', icon: 'delete', label: t('INBOX.MENU_ITEM.DELETE') },
 ]);
 
 const messageClasses = computed(() => ({