Update Flow Classify Hook design to support current requirements

### Describe the feature you'd like supported

The current [docs/FlowClassifyHook.md](https://github.com/microsoft/ebpf-for-windows/blob/main/docs/FlowClassifyHook.md) is out of date with the [FlowClassifyHookRequirements.md](https://github.com/microsoft/ebpf-for-windows/blob/main/docs/FlowClassifyHookRequirements.md) doc that was added in #5533.

We should develop a new/updated flow classify design doc so that the design covers all requirements.

### Proposed solution

Update/rewrite the design doc to support all required features in [FlowClassifyHookRequirements.md](https://github.com/microsoft/ebpf-for-windows/blob/main/docs/FlowClassifyHookRequirements.md).

### Additional context

This is follow-up to issue #5513. This is only a task for the design doc -- after the design is approved follow-up issues can be created for the specific work required to implement the design.

Start by reading docs/FlowClassifyHookRequirements.md and compare it with docs/FlowClassifyHook.md, using issue #5533 for the requirements context. Identify every requirement not covered by the current design and update or rewrite the design document so all requirements are addressed. Done means the design document covers the requirements and is ready for approval; implementation is out of scope.

Written by the indexing model from the issue text.