Fix MediaStreamVideoCapturerSource no-return-after-failure

In MediaStreamVideoCapturerSource, if SendWheel() or SetZoomLevel()
encountered a missing device ID, they invoke the callback,
but they failed to return immediately. Instead, they passed that
moved-from callback onwards to the MediaStreamDispatcherHost.

This CL fixes this issue.

Bug: 337847746
Change-Id: I29ddbf95d3fde50357a5190049db1175bffcadcc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5497319
Auto-Submit: Elad Alon <eladalon@chromium.org>
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Elad Alon <eladalon@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1293993}