Change MessageType values from decimals to hexadecimals for readability (#55985)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/55985
Test Plan: Imported from OSS
Reviewed By: nikithamalgifb
Differential Revision: D27758101
Pulled By: pbelevich
fbshipit-source-id: 45a7c4d1c4fea874bca7b96e7f2b699ce3a199e5
