Hey @NikhilBansal21. Oh, I think this is a bit annoying behaviour from Google testing side. I would suggest trying the following:
Go to permissions of your project on Google Actions console and add a new user with viewer permissions (you will need a different google account for that).
Once you do that, login to the account that has viewer permissions and you should be able to test you assistant. Alternatively - ues the Google Assistant App on your phone for testing.