Fixed an issue where change child position command packets inside macros could have been be truncated due to us assuming command packets would be 8 bytes. Now we allow arbitrary length. Actual handling of the lengths will be enforced by the deserializer.
(partially cherry picked from commit 798251171724c456ee74840f3dd9872832132d04)
(partially cherry picked from commit 798251171724c456ee74840f3dd9872832132d04)