Initialize env variable to resolve a number of debugger issues

[DonJayamanne]

Fixes #11033
Fixes #10600
Fixes #8146

This also fixes the debugger test failures that we're running into, see here microsoft/debugpy#1000.

Thought this could be merged, however we need to wait for a new version of debugpy to be published.
Until then this PR will be blocked.
However submitting this PR as i've already done the work (found while testing that theres no way to test as the changes haven't been released yet)

[codecov-commenter]

Codecov Report

Merging #11058 (347b3f8) into main (063cda0) will decrease coverage by 0%.
The diff coverage is 100%.

❗ Current head 347b3f8 differs from pull request most recent head 037f3f2. Consider uploading reports for the commit 037f3f2 to get more accurate results

@@           Coverage Diff           @@
##            main   #11058    +/-   ##
=======================================
- Coverage     63%      63%    -1%     
=======================================
  Files        484      483     -1     
  Lines      34085    33881   -204     
  Branches    5558     5526    -32     
=======================================
- Hits       21567    21417   -150     
+ Misses     10454    10409    -45     
+ Partials    2064     2055     -9     

Impacted Files	Coverage Δ
...interactive-window/debugger/startupCodeProvider.ts	90% <100%> (+1%)	⬆️
src/kernels/debuggerStartupCodeProvider.ts	100% <100%> (ø)
src/kernels/kernel.ts	82% <100%> (-1%)	⬇️
src/kernels/kernelStartupCodeProvider.node.ts	81% <100%> (+1%)	⬆️
src/kernels/serviceRegistry.node.ts	96% <100%> (ø)
src/kernels/kernelAutoReConnectFailedMonitor.ts	68% <0%> (-14%)	⬇️
src/kernels/kernelAutoReConnectMonitor.ts	67% <0%> (-13%)	⬇️
src/kernels/helpers.ts	59% <0%> (-6%)	⬇️
src/platform/common/cancellation.ts	59% <0%> (-6%)	⬇️
.../standalone/survey/dataScienceSurveyBanner.node.ts	66% <0%> (-4%)	⬇️
... and 49 more