Filebrowser Context Menu should exclude Shut Down kernel for documents that don't support a kernel

[ianhi]

Description

The context menu give the option to Shut Down Kernel even for documents that don't support one such as a .zip file and also for notebooks without a currently running kernel.

Continuation of #9960

Reproduce

Open filebrowser and right click on any non-folder item

Expected behavior

Shut Down Kernel only present in menu when there is a kernel to be shut down.

Context

• Operating System and version: Linux Ubuntu 21.04
• Browser and version: Firefox 93
• JupyterLab version: 3.2.1

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[jasongrout]

I think to do this well, it requires some changes in how the filebrowser exposes the selected items and the sessions it knows about, so the command can decide to disable itself if there are no current kernels running on the selected items. Presumably the command at

jupyterlab/packages/filebrowser-extension/src/index.ts

Lines 995 to 1005 in b228e5d

	commands.addCommand(CommandIDs.shutdown, {
	execute: () => {
	const widget = tracker.currentWidget;
	if (widget) {
	return widget.shutdownKernels();
	}
	},
	icon: stopIcon.bindprops({ stylesheet: 'menuItem' }),
	label: trans.__('Shut Down Kernel')
	});

would be able to determine what was selected and if any of the selected items had associated kernel sessions.

I also tried this, but it didn't seem to work.

diff --git a/packages/filebrowser-extension/schema/browser.json b/packages/filebrowser-extension/schema/browser.json
index c2a19defdf..24dc3dccd8 100644
--- a/packages/filebrowser-extension/schema/browser.json
+++ b/packages/filebrowser-extension/schema/browser.json
@@ -104,7 +104,7 @@
       },
       {
         "command": "filebrowser:shutdown",
-        "selector": ".jp-DirListing-item[data-isdir=\"false\"]",
+        "selector": ".jp-DirListing-item[data-isdir=\"false\"]:not(.jp-mod-running)",
         "rank": 11
       },
       {