Serverless mode does not correctly handle a missing license key

[nrcventura]

Description

When the agent is operating in serverless mode, it should not require a license key to be configured. The lambda extension that is responsible for transmitting the serverless data has 2 options for specifying the license key.

1. Using an AWS secrect to manage the license key
2. Using the license key environment variable

If both options are used the extension will log a warning that you should not configure both. If only the AWS secret is used, the .net agent won't start correctly and reports the following error.

There was an error initializing the agent
System.Exception: Please set your license key.
   at NewRelic.Agent.Core.AgentManager.AssertAgentEnabled()
   at NewRelic.Agent.Core.AgentManager..ctor()
   at NewRelic.Agent.Core.AgentManager.AgentSingleton.CreateInstance()

The current workaround is to specify the license key as an environment variable.

Expected Behavior

The .net agent should start successfully in serverless mode if the license key is not provided.

Steps to Reproduce

1. Configure a .net lambda to use the .net agent and lambda extension
2. Use an AWS secret to specify the license key
3. Enable logging for the lambda extension and the .net agent
4. Send an event to the lambda
5. Verify that the .net agent does not start correctly because of the missing license key

For Maintainers Only or Hero Triaging this bug
Suggested Priority (P1,P2,P3,P4,P5): P5
Suggested T-Shirt size (S, M, L, XL, Unknown): S

[workato-integration]

https://new-relic.atlassian.net/browse/NR-272645