Attempt suppressing a trace on boot failure.

[3405691582]

When a boot fails, we print a trace saying that run_cvd failed. This isn't strictly necessary or informative, so attempt to suppress this by just returning a CF_ERR instead of CF_EXPECT'ing that the executable returned successfully -- because we already know it didn't.

[3405691582]

I'm not sure if this will have the intended effect, because I'm not sure how to trigger this myself, but I'm assuming you'd have a slightly better idea here than I would.

[Databean]

I cherry-picked this change and additionally changed host/commands/start/main.cpp to immediately return -1; and it still produces this error:

Device launch failed, cleaning up
5. main.cc:152 | CvdMain | 
4. cvd.cpp:84 | HandleCvdCommand | 
3. cvd.cpp:69 | HandleCommand | 
2. create.cpp:363 | Handle | 
1. create.cpp:129 | StartGroup | 
 | cuttlefish/host/commands/cvd/cli/commands/start.cpp:564
 v Result<void> cuttlefish::CvdStartCommandHandler::LaunchDevice(Command, LocalInstanceGroup &, const cvd_common::Envs &, const CommandRequest &)
Device launch failed.

This PR cuts a level off the stack trace, but ultimately still produces the stack trace, which is still relatively noisy.

[Databean]

I've uploaded https://www.github.com/google/android-cuttlefish/pull/2826 to hide the stack traces created by cvd, it doesn't yet affect stack traces produced by assemble_cvd / run_cvd / etc.