Use environment NB Convert

[IanMatthewHuff]

For #14143

Trying to reopen this PR and have it actually work.

#14289

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR).
• Title summarizes what is changing.
• Has a news entry file (remember to thank yourself!).
• Appropriate comments and documentation strings in the code.
• Has sufficient logging.
• Has telemetry for enhancements.
• Unit tests & system/integration tests are added/updated.
• Test plan is updated as appropriate.
• package-lock.json has been regenerated by running npm install (if dependencies have changed).
• The wiki is updated with any design decisions/details.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
0 Code Smells

No Coverage information
0.0% Duplication

[codecov-io]

Codecov Report

Merging #14308 into main will decrease coverage by 0.50%.
The diff coverage is 22.58%.

@@            Coverage Diff             @@
##             main   #14308      +/-   ##
==========================================
- Coverage   59.91%   59.40%   -0.51%     
==========================================
  Files         709      712       +3     
  Lines       39334    40289     +955     
  Branches     5698     5942     +244     
==========================================
+ Hits        23567    23934     +367     
- Misses      14529    15085     +556     
- Partials     1238     1270      +32     

Impacted Files	Coverage Δ
src/client/datascience/commands/exportCommands.ts	14.70% <0.00%> (-0.45%)	⬇️
src/client/datascience/constants.ts	99.78% <ø> (+<0.01%)	⬆️
src/client/datascience/export/types.ts	100.00% <ø> (ø)
...ient/datascience/interactive-ipynb/nativeEditor.ts	7.78% <0.00%> (ø)
...atascience/interactive-window/interactiveWindow.ts	9.30% <0.00%> (ø)
...interpreter/jupyterInterpreterDependencyService.ts	76.57% <ø> (+6.41%)	⬆️
...er/jupyterInterpreterSubCommandExecutionService.ts	84.31% <ø> (-0.49%)	⬇️
src/client/datascience/jupyter/jupyterImporter.ts	16.04% <0.00%> (+0.38%)	⬆️
...science/jupyter/liveshare/guestJupyterExecution.ts	19.56% <ø> (+2.25%)	⬆️
...ascience/jupyter/liveshare/hostJupyterExecution.ts	59.09% <ø> (+1.11%)	⬆️
... and 21 more

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[IanMatthewHuff]

Finally got tests up for this. It's actually this PR here (which Rich and David already looked at) but recreated in a new branch and with tests working.

#14289