Lacros: Make ash::TryOpenUrl pretend to handle unexpected cases

When Lacros is enabled, this function should return false only for a
small fixed set of exceptions. Until now we used to also return false
for unexpected cases, so as to fall through to existing behavior at
call sites in order to not break anything. Looking at recorded stack
traces, there are no valid cases anymore. Hence change the function
to return true by default, thus preventing accidental creation of an
Ash browser window.

Keep the stack trace recording for now, as it may help us find bugs.

Bug: 332814568, b:332812810
Change-Id: Icf2fe244e19519cde801441f3003b9469e1db870
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5422989


Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1282975}