Two related failures on aggressively stripped Unity Mono builds:
1. InitializeLoggers reads Application.unityVersion, which the managed
code stripper can remove. The version is only used for an
informational log line, but a MissingMethodException there aborts the
rest of chainloader initialisation. Read it defensively instead.
2. UnityChainloader.Initialize caught every exception, logged it as
Fatal, and returned normally. StaticStart then called Execute() on a
chainloader that was never initialised, so BepInEx logged
"Chainloader startup complete" while every plugin silently never ran.
Rethrow so a failed init cannot be mistaken for a successful one.
Verified on Beacon Pines (Unity 2021.3.45f1, Mono, x64), which strips
both Application.unityVersion and the log-callback members.
Co-authored-by: ManlyMarco <39247311+ManlyMarco@users.noreply.github.com>
