feat: Added aws.lamda.arn tag for APM lambda entities

[DasuNewrelic]

Relevant information

As part of our work on Lambda Fusion, we're redirecting Lambda functions to APM. To identify which is Lambda entities APM view, we did some analysis and found an attribute called aws.lambda.arn, which is specific to Lambda functions. We're using this attribute as a tag for identification, and I've raised a PR for to create that attribute as a tag

Checklist

• I've read the guidelines and understand the acceptance criteria.
• The value of the attribute marked as identifier will be unique and valid.
• I've confirmed that my entity type wasn't already defined. If it is I'm providing an explanation above.

[davidgonzalez-nr]

Replicated changes into our STG testing PR #1966

please request to merge this PR once code is ready to go to production.