fix: make transfer restrictions work with wrap/unwrap changes

switch `address(this)` => `address(0)` to allow wrapping + unwrapping while transfer restrictions are in place

this aligns transfer restrictions with the modified wrap/unwrap behavior (where tokens are minted/burned instead of transferred from the token's own address)

src/contracts/token/Eigen.sol

@@ -155,7 +155,7 @@ contract Eigen is OwnableUpgradeable, ERC20VotesUpgradeable {
         if (block.timestamp <= transferRestrictionsDisabledAfter) {
             // if both from and to are not whitelisted
             require(
-                from == address(0) || from == address(this) || to == address(this) || allowedFrom[from] || allowedTo[to],
+                from == address(0) || to == address(0) || allowedFrom[from] || allowedTo[to],
                 "Eigen._beforeTokenTransfer: from or to must be whitelisted"
             );
         }

src/test/token/EigenWrapping.t.sol

@@ -202,7 +202,6 @@ contract EigenWrappingTests is Test {
 
         vm.startPrank(minter1);
         bEIGEN.setAllowedFrom(minter1, true);
-        eigen.setAllowedTo(address(0), true);
         vm.stopPrank();
 
     }