To connect Godaddy domain with Firebase Hosting with www redirect:
(Process to point www.yourdomain.com -> yourdomain.com)
Goto Godaddy portal -> Forwarding -> Subdomains -> Add Forwarding -> Enter subdomain as www -> Add destination url as yourdomain.com
Step 1 will add two A records
Goto Firebase hosting -> Connect Domain -> Enter domain yourdomain.com -> Connect
Add the A and TXT records provided by Firebase in the DNS records on Godaddy portal.
This steps worked for me & should solve the issue.