Extension should consider using vscode.open for browser launch

[auchenberg]

Hi Kenneth from the VS Code team here,

We noticed the launchBrowser attribute in the launch.json as this extension has it's own logic to launch browsers.

For future scenarios we recommend using the VS Code API vscode.open that can open a URL in the browser. It works on all platforms, so when the C# extension can invoke this command, then this should work.

[gregg-miskelly]

@auchenberg We launch the browser from the debugger, where we have no access to any VS Code API. To do this we will need a new debug protocol message for a debug adapter to request a browser to be opened.

CC @weinand @isidorn @egamma

[gregg-miskelly]

This issue is no longer needed. Support for this is handled by serverReadyAction.