Whitelist() function in the StableSwap keeper returns success (nil error) for non-existent pools. This goes against the functions intended purpose of validating pools for whitelisting.
When HasPool returns false, indicating the pool doesnt exist, the function returns nil instead of an error:
https://github.com/initia-labs/initia//blob/f5cd97d3aadd694d511c61ce5f55a772f4d2b904/x/move/keeper/stableswap.go#L54-L56
This allows non-existent pools to be whitelisted. Attackers could pre-whitelist addresses and later create pools with malicious configurations. This bypasses the entire whitelist check.
Add this test:
The whitelist() function should return an error when the pool doesnt exist.
