[OpenTelemetry.Instrumentation.AWSLambda] Do not crash on empty LambdaContext

[Dreamescaper]

Fixes #2445

Changes

Handle the case is InvokedFunctionArn is null in LambdaContext.

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Dreamescaper / name: Oleksandr Liakhevych (eeb9ec2, e6127a6)
• ✅ login: Kielek / name: Piotr Kiełkowicz (6ae5f32)

[Kielek]

Consider adding CHANGELOG entry.

[Dreamescaper]

@Kielek
Updated.

[ppittle]

@Dreamescaper - thank you for contributing the fix!

[Kielek]

Approving and merging based on @ppittle comment.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (71655ce) to head (6ae5f32).
Report is 677 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #2457       +/-   ##
==========================================
- Coverage   73.91%       0   -73.92%     
==========================================
  Files         267       0      -267     
  Lines        9615       0     -9615     
==========================================
- Hits         7107       0     -7107     
+ Misses       2508       0     -2508     

see 263 files with indirect coverage changes

[martincostello]

I just ran into this myself trying to update the package - is it possible to get a new version with this change released to NuGet?

[Kielek]

@martincostello, please check https://github.com/open-telemetry/opentelemetry-dotnet-contrib/issues/new?assignees=&labels=release&projects=&template=release_request.yml&title=%5Brelease+request%5D+

[martincostello]

#2461