Mounting rideable entities reorients player view south

When mounting a mob or minecart, the player will face south (+Z) rather than the direction either entities are facing. This appears related to MCPE-54715, however this occurs specifically when initially mounting.

Affects minecarts, horses, skeleton horses, pigs, llamas, donkeys, & mules; doesn't affect boats.

Notes: Doesn't occur if the player is already riding an entity and/or in third person view when mounting.