Add Front Door tracking reference to Application Insights logs

### Description

We would like to add the Front Door tracking reference id (the X-Azure-Ref header) to our Application Insights logs from our Isolated Function Apps so that it is easier to correlate data in App Insights. It appears that the is not supported using Isolated Functions - if it is I'd be interested to learn how.

Start by reviewing the isolated worker's Application Insights logging integration and how the Front Door X-Azure-Ref header is exposed to isolated Function Apps. Confirm whether the reference can reach Application Insights logs, and consider the work complete when it is reliably available for correlation.

Written by the indexing model from the issue text.