bug: index out of range when response code is not 200

Program crashed with an error index out of range on this line:

Line 63 in b7eff5a

    
           expiresIn, _ := strconv.Atoi(result.AuthToken.Expiration[:len(result.AuthToken.Expiration)-1])

My request payload was invalid and firebase API returned 40x code and no err (it's the behavior of client.Do). That's why we have to check resp.StatusCode after err != nil and return err if status is not http.StatusOK

go-android-firebase/client/client.go

Lines 45 to 48 in b7eff5a

    
           resp, err := c.Client.Do(req) 
        
           if err != nil { 
        
           	return nil, fmt.Errorf("c.Client.Do: %w", err) 
        
           }

	resp, err := c.Client.Do(req)
	if err != nil {
	return nil, fmt.Errorf("c.Client.Do: %w", err)
	}