<< CAVEAT >> Best practice is to follow the manufacturer's instructions for all operations of your pistol.
There are probably several pistols that require or allow one to pull the trigger as part of disassembly.
The Walther PPS M2 manual, after covering safely clearing the pistol, in step 5.1.1 says "Point the pistol in a safe direction. Squeeze the trigger fully to the rear."
The S&W M&P M2.0 has an integral tool that, after covering safely clearing the pistol, the owner's manual says to use to move the sear activation lever to the disassembly position. Alternatively, one can pull the trigger to release the slide.