"Worker" logs do not show up in app insights

[ejizba]

Per these docs, the "Worker" category logs are supposed to be showing up in the "traces" table for app insights, but they aren't. They show up in our internal kusto FunctionsLogs table and they are shown when running locally with core tools, but not in a user's app insights. These types of logs are crucial for the Node.js team to communicate with our customers and help them fix their own issues. I tested and these logs are actually missing for all languages, granted some workers log more information than others. Also, the app setting logging__logLevel__Worker has no effect in Azure, although it does help filter logs when running locally with core tools.

Repro steps:

1. Clone this sample Node.js app and deploy: https://github.com/ejizba/workerlogsexample
2. Hit the HttpTrigger1 url
3. Check app insights after several minutes have passed

Here are a couple sample logs, as seen from our kusto FunctionsLogs that we should be seeing in app insights

"Summary": Error: 'done' has already been called. Please check your script for extraneous calls to 'done'.,
"Source": Worker.LanguageWorkerChannel.node.c70ab712-70a6-4eca-88f1-d6e30f691a98,
"Level": 2,

"Summary": Worker was unable to load entry point "index2.js": abc123,
"Source": Worker.LanguageWorkerChannel.node.c70ab712-70a6-4eca-88f1-d6e30f691a98,
"Level": 3,

More information

This could arguably be a breaking change if these logs just started showing up all the sudden, especially since they can contain errors/warnings which the user may interpret as an urgent problem. I am open to ideas to fix this under a worker capability, feature flag, or whatever so that we can still get it fixed ASAP without worrying about breaking people.