Support configuring log levels/sampling overrides with java app insights agent

When using the [app insights java agent](https://learn.microsoft.com/en-us/azure/azure-monitor/app/monitor-functions), the only known way to configure log levels is by using sampling overrides as described in [these docs](https://learn.microsoft.com/en-us/azure/azure-monitor/app/java-standalone-sampling-overrides). However, it's not possible to add an "applicationinsights.json" file next to the agent jar file because it's stored/shipped with the worker, not the app.

[Related IcM](https://portal.microsofticm.com/imp/v3/incidents/details/425099857/home) (internal link only)