fix(aws-lambda): BasicTracerProvider not force flushing

[longility]

When the tracer provider is set, the type is a ProxyTracerProvider that proxies to the BasicTracerProvider. This unwraps and gets the delegate to attempt to force flush.

fixes #647

[codecov]

Codecov Report

Merging #661 (9912a64) into main (7edf984) will decrease coverage by 0.37%.
The diff coverage is n/a.

❗ Current head 9912a64 differs from pull request most recent head 67efa0a. Consider uploading reports for the commit 67efa0a to get more accurate results

@@            Coverage Diff             @@
##             main     #661      +/-   ##
==========================================
- Coverage   96.82%   96.44%   -0.38%     
==========================================
  Files           9       14       +5     
  Lines         630     1210     +580     
  Branches      124      171      +47     
==========================================
+ Hits          610     1167     +557     
- Misses         20       43      +23     

Impacted Files	Coverage Δ
...st/integrations/lambda-handler.force-flush.test.ts	96.66% <0.00%> (ø)
...strumentation-aws-lambda/test/lambda-test/async.js	100.00% <0.00%> (ø)
...nstrumentation-aws-lambda/test/lambda-test/sync.js	100.00% <0.00%> (ø)
...-instrumentation-aws-lambda/src/instrumentation.ts	90.84% <0.00%> (ø)
...ws-lambda/test/integrations/lambda-handler.test.ts	97.97% <0.00%> (ø)

[willarmiros]

@longility these comments should fix the unit tests (assuming no typos!)

[dyladan]

Looks good to me. One minor suggestion up to you

[willarmiros]

Thanks @longility! It looks like there are some lint errors to fix quickly.

This will unblock #660. @Flarna please take a look when you get a chance.

[longility]

Thanks @longility! It looks like there are some lint errors to fix quickly.

This will unblock #660. @Flarna please take a look when you get a chance.

I’m not at my desk so maybe at least two hours before I can get to it

[willarmiros]

@Flarna is this ready for merge?

[Flarna]

@willarmiros I have approved yes. Not sure about the general guidelines. At least in the past one or two of the otel-js maintainers had to approve but maybe this has changed in contrib repo.

[willarmiros]

Ah I didn't see that @dyladan had been re-requested for a review nvm - my bad.

[longility]

Ah I didn't see that @dyladan had been re-requested for a review nvm - my bad.

I figured I made enough changes for him to re-review to spot check. Sorry for the delay.