Remove TaskQueueBase::Current() from Call construction

This change removes implicit reliance on `TaskQueueBase::Current()`
during the instantiation of `Call`, `CallStats`,
`RtpTransportControllerSend`, and `TaskQueuePacedSender`. Task queue
pointers are now explicitly injected through configuration structures
rather than being resolved at runtime.

Key modifications include:
* Adding explicit `worker_task_queue` and `network_task_queue`
  parameters to `CallConfig` and related factories.
* Replacing `sequence_checker_` with explicit thread bounds using
  the injected `worker_thread_` in `RtpTransportControllerSend`.
* Removing the `GetCurrentTaskQueueOrThread()` fallback logic in
  favor of strict null checks on the injected queues.
* Providing `CreateWithJoinedWorkerAndNetworkQueue` to simplify
  configuration where worker and network queues are identical.

Bug: none
Change-Id: Iad95bf32018510cace5687abe71a035c26d11726
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/478960
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47913}