When debugging, the extension correctly uses custom .env files + Update tooltip

[karrtikr]

For #4537 #4849

• 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!)
• [ ] 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.

[DonJayamanne]

[ ] Unit tests & system/integration tests are added/updated

Why don't we have any tests?

[codecov]

Codecov Report

Merging #4906 into master will increase coverage by 34%.
The diff coverage is 100%.

@@ Coverage Diff @@ ## master #4906 +/- ## ========================================= + Coverage 63% 96% +34%  ========================================= Files 372 1 -371 Lines 14624 62 -14562 Branches 1159 9 -1150 ========================================= - Hits 9068 59 -9009  + Misses 5348 3 -5345  + Partials 208 0 -208

Addressed

[DonJayamanne]

No new tests have been added to validate this new fix!
We need new tests as the existing tests are not sufficient for new changes.

[karrtikr]

No new tests have been added to validate this new fix!
We need new tests as the existing tests are not sufficient for new changes.

I have modified existing tests to test that debugConfig envFile attribute contains the value that is mentioned in python.envFile setting. (which I think validates the fix)

I changed python.envFile settings to return the value ${workspaceFolder}/.env2 instead of ${workspaceFolder}/.env, so that the tests now fail on reverting the changes.

Please re-review