Two CLJ REPL Windows open on connect when `afterCLJReplJackInCode`is used

[PEZ]

The afterCLJReplJackInCode option of the Custom Connect Sequences are run in the REPL Window, in order for it to be visible and its results and printing side effects to be easy to find.

However, if the user has the calva.openREPLWindowOnConnect setting enabled, it will also open the CLJ window, and right now it results in that two window are opened:

• One that doesn't get a working prompt
• The other is where the afterCLJReplJackInCode is evaluated
  • Here the prompt works, however..
• Closing the first window will make the working prompt stop working

The fix here is to make sure only one window is opened per REPL session, and that this window is used for the custom after-connect commands.