Invalid kernel selection for IW with remote kernels

[DonJayamanne]

• Start IW
• Select a remote kernel spec and run a cell
• Go into kernel picker and select the active kernel session that points to this IW
• Things hang
  I think whats going on is, with IW kernel sessions are never persisted (unlike notebooks)
  However the controller that points to the kernel session is selected
  So the session is killed while also being used from another controller

Need to properly dispose the controller as soon as the other session is shutdown.
Ugly scenario

[DonJayamanne]

The cause is

• For IW, when starting remote kernels, we will shut those remote kernel sessions
• Thus when switching kernels, the previous kernel is shutdown and then we attempt to connect to the live kernel
• However the live kernel no longer exists, as the previous kernel ws the same as the live kerfnel, and the previous/live kernel was shutdown

This only applies to IW, as we always shtudown remote kernels started by us
With notebooks we never shut them down.

One way of address this is to simply have one controller for remote kernels.
I.e. fix #9865

        // If this Interactive Window, then always shutdown sessions (even with remote Jupyter).
        if (this.resource && getResourceType(this.resource) === 'interactive') {
            return true;
        }