Use enums for telemetry event names

[DonJayamanne]

For #2904 (part 1 for #2904)

• 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!)
• [n/a] Unit tests & system/integration tests are added/updated
• [n/a] Test plan is updated as appropriate
• [n/a] package-lock.json has been regenerated by running npm install (if dependencies have changed)

[codecov]

Codecov Report

Merging #3992 into master will decrease coverage by 24%.
The diff coverage is 84%.

@@           Coverage Diff            @@
##           master   #3992     +/-   ##
========================================
- Coverage      78%     55%    -23%     
========================================
  Files         406     327     -79     
  Lines       18929   13770   -5159     
  Branches     3034    2137    -897     
========================================
- Hits        14659    7486   -7173     
- Misses       4268    5793   +1525     
- Partials        2     491    +489

Flag	Coverage Δ
#Linux	?
#Windows	?
#macOS	?

Impacted Files	Coverage Δ
...lient/unittests/common/managers/baseTestManager.ts	8% <10%> (-74%)	⬇️
...nguageServer/languageServerCompatibilityService.ts	100% <100%> (+7%)	⬆️
src/client/telemetry/constants.ts	100% <100%> (ø)	⬆️
src/client/workspaceSymbols/provider.ts	94% <100%> (-3%)	⬇️
.../extension/configuration/providers/djangoLaunch.ts	87% <100%> (+1%)	⬆️
.../client/application/diagnostics/commands/ignore.ts	100% <100%> (+10%)	⬆️
.../extension/configuration/providers/moduleLaunch.ts	88% <100%> (-1%)	⬇️
...reter/locators/services/cacheableLocatorService.ts	82% <100%> (-15%)	⬇️
...debugger/extension/configuration/resolvers/base.ts	96% <100%> (ø)	⬇️
...r/extension/configuration/providers/flaskLaunch.ts	86% <100%> (+5%)	⬆️
... and 370 more

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[codecov]

Codecov Report

Merging #3992 into master will increase coverage by 1%.
The diff coverage is 85%.

@@           Coverage Diff           @@
##           master   #3992    +/-   ##
=======================================
+ Coverage      79%     79%    +1%     
=======================================
  Files         409     410     +1     
  Lines       19024   19124   +100     
  Branches     3035    3052    +17     
=======================================
+ Hits        14845   14926    +81     
- Misses       4177    4190    +13     
- Partials        2       8     +6

Flag	Coverage Δ
#Linux	68% <73%> (ø)	⬇️
#Windows	68% <74%> (ø)	⬇️
#macOS	68% <74%> (ø)	⬇️

[d3r3kk]

I have a question about this change. Why wouldn't we also consider changing /src/telemetry/index.ts to make the captureTelemetry function look like so?

export function captureTelemetry(
    eventName: EventName, // <= take advantage of this new enum...
    properties?: TelemetryProperties,
...

It's not strictly necessary to make this change of course, but I expected to see this and was wondering why it isn't there.

(This also applies to the other exported functions in .../telemetry/index.ts: sendTelemetryEvent and sendTelemetryWhenDone)

[DonJayamanne]

@d3r3kk

I have a question about this change. Why wouldn't we also consider changing /src/telemetry/index.ts to make the captureTelemetry function look like so?

That's part 2,
If you look at the comments in the PR i've mentioned this is Part 1, smaller PR easier to review. Else the changes get bigger...

[DonJayamanne]

Please re-review