Fix compatibility with retroactive C++23 change in webrtc_overrides

In https://reviews.llvm.org/D119136, clang now emits a warning when a
lambda capture variable shadows a structured binding. This is causing
the Chromium build bots to fail. To fix this, we rename the capture
variable.

Change-Id: I98afe2d02de9608fd2c6508c9cabe08e9d0c01e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3586057
Reviewed-by: Arthur Eubanks <aeubanks@google.com>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#993109}