Customizable Marketplace message for denylisted extensions and extension updates

[jvilk-stripe]

This feature request is an add-on to the extension allowlist/denylist under development in #84756. cc @isidorn who requested that this be filed as a separate request.

The VS Code Marketplace is a great place for engineers to discover new extensions directly in their editor. We would love to maintain the usability of this Marketplace even with a strict allowlist policy in place so that our engineers have actionable information on what to do to allowlist an extension (or its update) within our organization.

Organizations will have different procedures for modifying the allowlist. Stripe has an online approval flow for new software dependencies that would be augmented with VS Code extensions once the allowlist functionality is available. Users would need to navigate to this form, fill it out for the specific extension and version, and get it approved.

It would be wonderful if VS Code supported modifying the message that shows up or is displayed when an extension is denylisted. If the message could be templated with the extension_id and version, we could even render a link directly to a pre-filled out web form, which would remove a lot of the friction from allowlisting a new extension.

For example, we might render something like:

$extension_id@$extension_version is not an approved VS Code extension at Stripe. You can begin the approval for this extension at http://go/vscode-extn/$extension_id@$extension_version

Ideally, the link would be clickable and redirect to the relevant form, with most fields pre-filled out.

If there is no UI space for an interactable message like this, then I would also accept a configurable URL (templated with extension ID and version) that is put somewhere for the user to visit for more info; we could link to a templated help document that then links to the form if the user decides they want to allowlist the extension. (Maybe a "More info" button or link?)

[CW-Willow]

Very useful.+1 pls.