Fix mojo connection for non-broker browser process and child process in ipcz mode.

On Lacros, Chrome is not always the broker. Therefore,
ContentBrowserClient provides a BindBrowserControlInterface to provide
an interface for communication between external processes and the
browser process. However, in ipcz mode, using this function will cause
the child process to be unable to establish a connection with the
browser process.

Bug: 1447576
Change-Id: I0d27cfe88e7d94685787c7936a510d5652a4c849
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4929586
Commit-Queue: Bo Liu <boliu@chromium.org>
Reviewed-by: Bo Liu <boliu@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1209418}