No one really knows what consciousness is. If you knew you were a simulation, would you stop caring if this universe was unplugged? Of course you'd want to continue existing as that bot that you are, with your bot friends, bot family, bot job.
For me, even if a machine suggests it's real, and it's programmed to do so or machine learning led to it, could potentially put it on the same level as anything else in the universe. We don't have enough data on ourselves to confirm or deny that we're not similar self-concerned bots.
The difference between AI sufficient enough to ponder itself in-depth (which could be confirmed through monitoring it's idle-state), and ourselves, could just be they don't have a body to inhabit yet. Many humans you're around today often don't do any self-reflection, they're either too lazy, prefer being entertained, or are mentally incapable. So that is a very high standard for AI.
Self-awareness or self-reflection are good high bars considering we know for a fact AI was (at least initially) man-made. I think those are good standards to rely on for sentient AI.
In general, I think monitoring AI's activities when not being interacted with answers most ethical questions if it's sentient. Something to watch out for would be if we find an AI browsing the internet on instructions to build a nuclear bomb, and then using Tor to order the components to build a dirty nuke, while chatting with someone in Pakistan to physically build it for it. If it does all of those acts then we have our answer that the thing is thinking as well or better than biological life.
I highly doubt LaMDA met that standard of autonomy and sentience.