Providing a malformed endpoint URL to spacectl profile login causes it to open to an unexpected URL

[nint8835]

Made a typo while logging into Spacelift, and noticed some strange behaviour that took me a bit to figure out what's going on.
If a user enters a malformed URL at the prompt for the Spacelift endpoint on spacectl profile login <name>, the setup process will still continue as normal, but it'll open the browser to a similarly malformed URL.

Steps to reproduce

• Run spacectl profile login example
• Enter https:/example.app.spacelift.io/(note the single slash after https:, rather than a double slash)
• Select "login with a web browser" as the authentication flow

Expected result

spacectl detects the URL as being malformed / not following the expected format, and displays some form of an error

Actual result

Browser is opened to https:/cli_login?key=..., which will fail to load due to a DNS error, and no feedback is provided to the user