Improve Isolated Http dispatch debuggability

In a recent .NET Isolated CRI https://portal.microsofticm.com/imp/v5/incidents/details/702096432/summary, during the impacted time ranges, logs were showing http requests being dispatched from host, then log silence for 15+ seconds followed by a TimeoutException coming from the **DefaultHttpCoordinator** [here](https://github.com/Azure/azure-functions-dotnet-worker/blob/e99be73f6c1b0d1a59b1788516675a82272667bb/extensions/Worker.Extensions.Http.AspNetCore/src/Coordinator/DefaultHttpCoordinator.cs#L63).

It's unclear what the problem is here since we don't have any more visibility into the GRPC communications for this invocation. The _theory_ was that high load/cpu caused delays, but if possible it'd be good if we can improve logs to make this clear.

In the incident above, I share all the relevant queries.

Start with extensions/Worker.Extensions.Http.AspNetCore/src/Coordinator/DefaultHttpCoordinator.cs at the linked timeout path, then trace the isolated HTTP dispatch and GRPC communication logging around it. Done means the logs make the period between host dispatch and TimeoutException clearer, including enough context to distinguish delayed communication from high load or CPU effects.

Written by the indexing model from the issue text.