[CSC] Flip CapturedSurfaceControlKillswitch to default-on

With the Chrome UX for Captured Surface Control complete,
it is now possible to make the permissions scoped to the
origin rather than to the capture-session.

Bug: 1466247, 324468211
Change-Id: I1ee17463e0012b5d09972a42b7a84083462bceae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5411131


Commit-Queue: Elad Alon <eladalon@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Auto-Submit: Elad Alon <eladalon@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1282159}