greengrass lambda does not register as a lambda environment

[stampcli]

The following line determines if the code is running as a lambda:

aws-embedded-metrics-python/aws_embedded_metrics/environment/lambda_environment.py

Line 32 in 658b2eb

return len(get_env("AWS_LAMBDA_FUNCTION_NAME")) > 0

Unfortunately the environment variables for lambdas are not provided by greengrass' version of lambdas. This means my aws-embedded-metrics agent attempted TCL connections from my greengrass lambda and was failing until I manually added AWS_LAMBDA_FUNCTION_NAME as an env variable with the function name.

[tuncali]

In Greengrass lambda environments, MY_FUNCTION_ARN environment variable is provided by Greengrass core. Adding a check on that environment variable would fix the issue for lambda functions running in a Greengrass core.