Improve remote jupyter server CORS warning/error message prompt

[DonJayamanne]

TODO:

• Provide ability for 3rd party Jupyter Server providers the ability to provide custom protocols for Web Sockets.

Other?

[DonJayamanne]

Improve UX in remote URL input for vscode.dev (able to copy url, etc)

[DonJayamanne]

The following UX needs to be improved

• The URL cannot be copied
• Error message with link is not where the validation error message is displayed (disconnected UX)
• Check with @TylerLeonhardt what can be done to add links (commands) to the validation error message

[TylerLeonhardt]

Check with @TylerLeonhardt what can be done to add links (commands) to the validation error message

That's tracked with microsoft/vscode#82112

[DonJayamanne]

• Add ability to copy the URL if there is one in the error message
• Display a link for the URL in the error message
• Display a tooltip or the like for quick pick item Install Python
• :deferred: Display a tooltip or the like for quick pick item that correspond to Conda environments without Python

[DonJayamanne]

Verification steps:

• Use VS Code insiders
• Go into kernle picker and select Eixisting Jupyter Server
• Attempt to add an invalid URL
• The error message should contain the URL and it should be a link that can be clicked.