fix(start): run update on start before applying game fixes (#5209)
`command_start.sh` ran `fix.sh` before the `updateonstart` block. Some game fixes export into the shell that runs the script (for Rust, `fix_rust.sh` exports `LD_LIBRARY_PATH` and sources the Carbon `environment.sh`), so the in-process update then ran SteamCMD with the game's environment still set and `steamcmd.sh` aborted.
`fix.sh` now runs after the update-on-start block. The separate `fix_ahl.sh` call after an update is removed, as `ahl` is covered by `fix.sh`.
Fixes #4753