I’m sorry but this is not correct.
While I can understand some people may want to turn off the lamp check feature when using LED lights, doing it solely to extend the life of the LED’s is a misnomer.
LED’s are not in any way affected by being pulsed, such as the lamp check signal you are referring to.
Pulsing LED’s is actually a very energy efficient way of reducing their brightness and is commonly found is all sorts of applications such as LED clocks, the backlight in your phone/tablet, and even LED TV’s.
While it is true LED’s lose some of their brightness over time (many years), this really only applies to the new super bright ones such as those used in LED floodlights and some of the brighter replacements for household halogen globes.
The key here is that the LED’s that are warm/hot when running will have a diminishing light output over time; manufacturing quality also plays a big part with this too.