Fixed type mismatch during inital OnAvatarEyeHeightChanged call

[Nestorboy]

When a player joins, OnAvatarEyeHeightChanged is invoked with the prevEyeHeightAsMeters parameter passed as the literal integer 0, causing a type mismatch since it is expected to be a float.

The issue was brought to my attention by another user using one of my prefabs: https://github.com/Nestorboy/NUMovement/issues/3