M49440: Fixing alt name of image according to image name

Translator has reported possible source content issue. 
Description: "List groups in an administrative unit" seems to be correct.

Author: v-maudel

articles/active-directory/users-groups-roles/roles-admin-units-add-manage-groups.md

@@ -70,7 +70,7 @@ Example:
 
 Go to **Azure AD > Administrative units** in the portal. Select the administrative unit for which you want to list the users. By default, **All users** is selected already on the left panel. Select **All groups** and on the right you will find the list of groups that are members of the selected administrative unit.
 
-![Select an administrative unit to delete](./media/roles-admin-units-add-manage-groups/list-groups-in-admin-units.png)
+![List groups in an administrative unit](./media/roles-admin-units-add-manage-groups/list-groups-in-admin-units.png)
 
 ### PowerShell