List global python kernelspecs

[DonJayamanne]

For #6622

[codecov-commenter]

Codecov Report

Merging #6676 (1776c0f) into main (ee7729a) will decrease coverage by 0%.
The diff coverage is 44%.

❗ Current head 1776c0f differs from pull request most recent head 2ef68f1. Consider uploading reports for the commit 2ef68f1 to get more accurate results

@@          Coverage Diff           @@
##            main   #6676    +/-   ##
======================================
- Coverage     69%     69%    -1%     
======================================
  Files        412     412            
  Lines      28473   28499    +26     
  Branches    4241    4249     +8     
======================================
- Hits       19825   19705   -120     
- Misses      6991    7124   +133     
- Partials    1657    1670    +13     

Impacted Files	Coverage Δ
.../localPythonAndRelatedNonPythonKernelSpecFinder.ts	80% <41%> (-7%)	⬇️
...ience/kernel-launcher/localKernelSpecFinderBase.ts	81% <66%> (-1%)	⬇️
...ience/variablesView/variableViewMessageListener.ts	22% <0%> (-78%)	⬇️
...ent/common/application/webviewViews/webviewView.ts	14% <0%> (-72%)	⬇️
...c/client/datascience/variablesView/variableView.ts	18% <0%> (-62%)	⬇️
src/client/datascience/webviews/webviewViewHost.ts	19% <0%> (-53%)	⬇️
...on/application/webviewViews/webviewViewProvider.ts	80% <0%> (-20%)	⬇️
.../datascience/variablesView/variableViewProvider.ts	65% <0%> (-16%)	⬇️
...lient/datascience/variablesView/notebookWatcher.ts	80% <0%> (-14%)	⬇️
src/client/datascience/webviews/webviewHost.ts	80% <0%> (-7%)	⬇️
... and 11 more

[DonJayamanne]

Will add tests later, after i finish ipykernel6 stuff (seprate PR)

[DonJayamanne]

Fixes tests with failing code completion (this is a bug in jupyter, changes are breaking us, the return value is different)
We already have an issue to fix the underlying bug (this way this test passes)