fix: redirect unauthenticated users from My Channels to public catalog

[Abhishek-Punhani]

Summary

• Updated "Explore without an account" link in AccountsMain.vue: Changed the href from /channels to /channels/#/public to directly load the public channel catalog for guests.
• Added redirect logic in ChannelList.vue: In the created() hook, check if the list type is editable (My Channels) and the user is not authenticated, then redirect to the public catalog (CATALOG_ITEMS), replacing the history entry to fix back navigation.

References

#5482

Reviewer guidance

• Sign out of Studio and visit the login page.
• Click "Explore without an account" – it should load the public catalog directly without errors.
  Manually navigate to /my-channels (or use the URL) – it should redirect to /public instantly, replacing the history.
• Click the browser back button – it should return to the login page (not a spinner).
• Sign in and access "My Channels" – it should load personal channels normally.