Why?

If I pick a random 1-5 character password out of the pool of possibilities, it's very very likely to be 5 characters, and letting you know it's not 1-4 characters does pretty much nothing to help you crack it.

If I'm acting reasonably, I don't randomize the length, I pick a length long enough for the amount of security I want, and in that situation telling you the exact length reduces that security by much less than one bit.