I have several Git remotes for Heroku apps, but I haven't logged in via heroku-cli. Sourcetree prompts me to enter credentials for each remote and if I click Cancel, a new one will appear. I don't want to log in. I want to disable those prompts. Currently I'm not able to use Sourcetree.

The prompts contain:
Authentication Required
For URL: https://git.heroku.com/...
Username:
Password:
[ ] Store Password In Keychain
Cancel / OK