jupyter-adapter: Tail of log files isn't flushed to output channel on exit

[lionel-]

To reproduce, start a Jupyter runtime and close it. Compare the runtime log in the output pane to the actual log file (the path should be on the second line in the output after [Positron] Streaming log file:). The output is missing the trailing lines because the logger is shut down before new line events have had time to fire up.

[DavisVaughan]

I see those trailing lines that were previously missing from your output channel now. I also confirmed this contains everything that my kernel.log file had in it!