[BUG] wasm default config is not properly set

[yun-yeo]

Describe the bug
To prevent someone provides zero write-vm-memory-cache-size, we tried to overwrite the config to default value instead zero.
That overwrite is happening in wrong place, so it does not have effect.

To Reproduce
provlem zero write-wasm-vm-cache

Context & versions
v0.5.6

(if applicable) suggested solution
move that replace code location to before write vm creation