Unnecessary modifier, onlyWhitelisted

The modifier onlyWhitelisted is empty and serves no purpose since the Merkle proofs are already being verified in the isWhitelisted function, which is subsequently called. To simplify the code and avoid unnecessary checks, the onlyWhitelisted modifier can be safely removed.

modifier onlyWhitelisted(
		address user,
		bytes32[] calldata merkleProof,
		Whitelists.MerkleProofWhitelist[] storage whitelist
	) {
		_;
	}

This issue has been acknowledged by Mighty Bear Games, and fixes were implemented in the following commits:

• 6dfe0373↗
• cf1cca87↗