Live Preview "Host IP" setting does not support IPv6 addresses

Background

Support for specifying custom IP addresses was added by @andreamah as part of https://github.com/microsoft/vscode-livepreview/pull/117

The specific commit that adds this feature is 145f83606455f0b53f175f05142aa3a2d6632ea2 which has the following code snippet

https://github.com/microsoft/vscode-livepreview/blob/145f83606455f0b53f175f05142aa3a2d6632ea2/src/infoManagers/connectionManager.ts#L143-L149

Proposal

I propose that this code is changed so that it uses the NodeJS standard library's net.isIP which can properly validate IP addresses, and handle both IPv4 as well as IPv6

Next Steps

I think this would be a fairly simple fix, which I'm happy to code this up myself and submit a pull-request with the corresponding changes. Are there any other places I'd need to change, aside from connectionManager.ts? Is using a NodeJS library possible in the context of this extension? Or would I have to use an API from the front-end JavaScript side of things?