I haven't seen polls on this exact scenario (doubt there are any) but I sincerely doubt there were that many people waiting on bated breath to see which candidate Liz Cheney was going to endorse before voting lockstep with that choice.
@mctoasterson I agree with that, however her words carry great weight with Republicans, so this will likely help push more Republicans to vote for Harris
If she could get Mitt Romney, her dad Dick Cheney and his wife (her mom) Lynn, George W. Bush and wife Laura, Jeb Bush, and a couple of southern Republican senators onboard with her, it might carry some weight.