I'm pretty sure Tesla has proofed their cars to handle lightning strikes nearby while charging. Lightning is common in Central/Eastern US, and there are thousands of drivers who park their cars and plug them in, then go to bed. Nothing happens. I'd like to know of anyone who has had damage to their car simply because lightning struck within a mile of their charging car.
It's like saying you need to unplug your refrigerator and air conditioner whenever there's a storm. It's not a thing.
Lightning has an insane amount of electrical power. Something like 30,000 Amps and 300,000,000 volts of electricity.
That’s so much power you really can’t expect to prevent issues with the many electrical systems on the car. It is orders of magnitude more power than the car is designed to handle while supercharging (~250kW = 800 amps). You can’t really engineer away that much power. Tesla engineers don’t have magic voodoo to protect the internal systems. Lightning has so much power and is so unpredictable, you can only dissipate so much energy and it will still overpower almost everything.
Your fridge or your air conditioner don’t take six months of queue, and $60k to replace. And they don’t drive you to work/school/store. So it’s less of a big deal when they go out. You just get a new one.
Lightning strikes commonly wreak havoc on things in homes when they strike nearby. Every homeowner should place a whole house surge protector in their main electrical panel to give them the maximum amount of protection against random surges.
But a best practice would definitely be to safe guard your vehicle if there are reports of lightning in your area, or high chances of electrical storms. I would rather not charge and 100% have my car the next day, than take the chance something could happen to it in the unlikely event of a direct lightning strike.