chore(contracts): simplify prover withdrawals (#82)

Author: mattstam

contracts/.gas-snapshot

@@ -111,4 +111,4 @@ SuccinctVAppStateTest:test_Step_WhenValid() (gas: 120853)
 SuccinctVAppStateTest:test_Step_WhenValidTwice() (gas: 177445)
 SuccinctVAppWithdrawTest:test_RevertWithdraw_WhenBelowMinimum() (gas: 27115)
 SuccinctVAppWithdrawTest:test_RevertWithdraw_WhenZeroAddress() (gas: 26810)
-SuccinctVAppWithdrawTest:test_Withdraw_WhenValid() (gas: 503946)
+SuccinctVAppWithdrawTest:test_Withdraw_WhenValid() (gas: 503997)

contracts/src/SuccinctVApp.sol

@@ -224,11 +224,8 @@ contract SuccinctVApp is
         //
         // Otherwise if the `_to` is not a prover vault, we can just transfer the $PROVE directly.
         if (ISuccinctStaking(staking).isProver(_to)) {
-            // Deposit $PROVE to mint $iPROVE, sending it to this contract.
-            uint256 iPROVE = IERC4626(iProve).deposit(amount, address(this));
-
-            // Transfer the $iPROVE from this contract to the prover vault.
-            IERC20(iProve).safeTransfer(_to, iPROVE);
+            // Deposit $PROVE to mint $iPROVE, sending it to the prover vault.
+            IERC4626(iProve).deposit(amount, _to);
         } else {
             // Transfer the $PROVE from this contract to the `_to` address.
             IERC20(prove).safeTransfer(_to, amount);