Do not cache active interpreter controller in notebookControllerManager

[joyceerhl]

Fix #7301

Root cause is we were caching the controller corresponding to the active interpreter and never clearing it out when the interpreter changes. I don't think we should be caching the active interpreter controller in the controllerManager because it's already cached in the pythonApi (and the pythonApi class also already bears responsibility for clearing out its cache on an interpreter change), so we would be duplicating the same code in two spots for no real benefit.

Also fixed a bug with our logic to preload the kernel corresponding to the active interpreter. It was always preloading the interactive controller, not the jupyter-notebook controller.

[codecov-commenter]

Codecov Report

Merging #7302 (17cc7cc) into main (a954838) will decrease coverage by 0%.
The diff coverage is 62%.

@@          Coverage Diff          @@
##            main   #7302   +/-   ##
=====================================
- Coverage     62%     62%   -1%     
=====================================
  Files        360     360           
  Lines      22535   22530    -5     
  Branches    3402    3401    -1     
=====================================
- Hits       14077   14070    -7     
  Misses      7282    7282           
- Partials    1176    1178    +2     

Impacted Files	Coverage Δ
.../datascience/notebook/notebookControllerManager.ts	84% <62%> (-1%)	⬇️
src/client/datascience/activation.ts	86% <0%> (-6%)	⬇️
src/client/common/cancellation.ts	72% <0%> (-4%)	⬇️
...t/datascience/notebook/vscodeNotebookController.ts	78% <0%> (-2%)	⬇️
src/client/datascience/baseJupyterSession.ts	61% <0%> (-1%)	⬇️
src/client/datascience/jupyter/jupyterNotebook.ts	21% <0%> (+<1%)	⬆️
src/client/datascience/raw-kernel/rawSocket.ts	84% <0%> (+1%)	⬆️
...tascience/jupyter/kernels/kernelCommandListener.ts	58% <0%> (+2%)	⬆️
src/client/common/application/applicationShell.ts	22% <0%> (+4%)	⬆️