Why is limit of callstack 5?

[da1suk8]

Currently, the limit of the call stack is defined as 5. It is mainly used in the following codes.

https://github.com/Finschia/cosmwasm/blob/eda535b09ef7501752d633eb32eebc46cb1c9b92/packages/vm/src/environment.rs#L15

https://github.com/Finschia/cosmwasm/blob/eda535b09ef7501752d633eb32eebc46cb1c9b92/packages/vm/src/environment.rs#L357-L359

https://github.com/Finschia/cosmwasm/blob/eda535b09ef7501752d633eb32eebc46cb1c9b92/packages/vm/src/environment.rs#L383-L385

Check callstack limits and fix if necessary.