Incorrect profile specification can cause profile validation to hang

[MarkAckert]

Is your feature request related to a problem? Please describe.

If a user enters the host value of a profile incorrectly with the format protocol:host, then profile validation can hang due to an unreachable network endpoint. e.g.

            "properties": {
                "host": "https://my.host.name",
                "port": 443,
                "rejectUnauthorized": false,
                "protocol": "https"
            },

Describe the solution you'd like

Zowe Explorer can detect host values which include a protocol and short-circuit the validation before hitting the /zosmf/info endpoint.

In addition / alternatively, Zowe Explorer validation shouldn't hang for an unreachable endpoint, I'd expect a network error response.

Describe alternatives you've considered

Additional context

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[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[awharn]

This issue seems to be caused by the VSCode proxy. When the proxy support is disabled, the request immediately fails due to a DNS lookup failure. When the proxy is enabled, the request hangs forever.