[bug] Lambda integration fails if no InvokedFunctionArn present

[Dreamescaper]

Component

OpenTelemetry.Instrumentation.AWSLambda

Package Version

Package Name	Version
OpenTelemetry.Instrumentation.AWSLambda	1.10.0-beta.3

Runtime Version

net8.0

Description

When I invoke lambda function locally during testing, providing an empty LambdaContext, it fails with the following error:

Error Message:
   System.NullReferenceException : Object reference not set to an instance of an object.
  Stack Trace:
     at OpenTelemetry.Instrumentation.AWSLambda.Implementation.AWSLambdaUtils.GetFaasId(String functionArn)
   at OpenTelemetry.Instrumentation.AWSLambda.Implementation.AWSLambdaUtils.GetFunctionTags[TInput](TInput input, ILambdaContext context, Boolean isColdStart)
   at OpenTelemetry.Instrumentation.AWSLambda.AWSLambdaWrapper.OnFunctionStart[TInput](TInput input, ILambdaContext context, ActivityContext parentContext)
   at OpenTelemetry.Instrumentation.AWSLambda.AWSLambdaWrapper.TraceInternalAsync[TInput,TResult](TracerProvider tracerProvider, Func`3 handlerAsync, TInput input, ILambdaContext context, ActivityContext parentContext)

Additional Context

I realize that it is not nessesseraly a bug, and I probably should add values there. But it didn't happen with 1.10.0-beta.1, and I can see that other methods (apart from GetFaasId, like GetAccountId) do check for functionArn nullabilty, so it probably should happen here as well.

[github-actions]

Tagging component owner(s).

@srprash @ppittle @muhammad-othman @rypdal @Oberon00