The leash position on many mobs does not have the correct offset

Verification builds: Release 924386 - 1.5.0.4 BETA
Summary: The leash position, when you attach a leash to them, is in the middle of the sky above the following mobs heads or otherwise incorrectly positioned.

cave spider, magma cube, spider, guardian, enderman, endermite, silverfish, wither, bat, creeper, dolphin, parrot, pufferfish, salmon, tropical fish, vex, turtle

Repro Steps:

1. Download the 'super behavior bug test time' (tm) map from Greg on Slack
2. summon any of the listed mobs
3. tame them with a beetroot to add the leashable component
4. attach a lead to them

Observed Results:

1. the lead is attached to the air above them, or in worse cases like the enderman, to its crotch so it looks phallic

Expected Results:

1. the lead should attach to the mob in an appropriate area

Impact: just looks kinda dumb, but isn't game breaking.

Mobs it's bugged on:
cave spider, magma cube, spider, guardian, enderman, endermite, silverfish, wither, bat, creeper, dolphin, parrot, pufferfish, salmon, tropical fish, vex, turtle