Lab extension makes a blocking call to the server extension on startup

Description

The front-end scheduler extension makes a blocking network call to the server extension in its start-up activatePlugin function:

jupyter-scheduler/src/index.tsx

Lines 154 to 156 in 1b50f81

    
           // Call API to verify that the server extension is actually installed 
        
           try { 
        
             await api.getJobs({ max_items: 0 });

This can cause a delay in JupyterLab startup, even if the user does not intend to use the scheduler extension.

Expected behavior

The scheduler should make asynchronous calls during its activatePlugin function.

	// Call API to verify that the server extension is actually installed
	try {
	await api.getJobs({ max_items: 0 });