Revert "Cleaned up Zeny manipulation in scripts."

Reverted due to a serious regression.
I'll commit this again once I fixed the issue in the script engine.
Sorry for the inconvenience.

This reverts commit 4faa0ec9df7067cee3eb1c1953fccc6c2f842179.

Signed-off-by: Haru <haru@dotalux.com>