Remove the need for passing NODE_TLS_REJECT_UNAUTHORIZED=0 when interacting with Spin environments

[pepicrft]

Resolves https://github.com/Shopify/shopify-cli-planning/issues/322

WHY are these changes introduced?

Spin stores the CA certificate for HTTPS connections in the local environment's keychain, and because Node doesn't use them, Shopifolks trying to use the CLI with Spin run into issues that they workaround by invoking the CLI with the NODE_TLS_REJECT_UNAUTHORIZED=0 environment variable. That's not ideal because the environment variable applies to all the HTTP requests, including the non-Spin ones.

WHAT is this pull request doing?

I'm taking an intermediate step towards the ideal solution (i.e. reading and using the certificates from the Keychain), which consists of using an https.Agent that has the right configuration to skip the TLS validation when we interact with Spin environments.

How to test your changes?

Try to log out, log in, and dev the fixture app.

[github-actions]

We detected some changes at packages/*/src and there are no updates in the .changeset.
If the changes are user-facing, run "yarn changeset add" to track your changes and include them in the next release CHANGELOG.