fix(ctb): L2OutputOracle event order bug

Fixes a small bug where event parameters were being emitted in the wrong
order. Adds a test to confirm correct ordering.

packages/contracts-bedrock/.gas-snapshot

@@ -139,11 +139,11 @@ L2ERC721Bridge_Test:test_finalizeBridgeERC721_succeeds() (gas: 168905)
 L2OutputOracleTest:test_computeL2Timestamp_succeeds() (gas: 37184)
 L2OutputOracleTest:test_constructor_badTimestamp_reverts() (gas: 70717)
 L2OutputOracleTest:test_constructor_succeeds() (gas: 33760)
-L2OutputOracleTest:test_deleteL2Outputs_afterLatest_reverts() (gas: 200230)
+L2OutputOracleTest:test_deleteL2Outputs_afterLatest_reverts() (gas: 211900)
 L2OutputOracleTest:test_deleteL2Outputs_ifNotChallenger_reverts() (gas: 18883)
-L2OutputOracleTest:test_deleteL2Outputs_nonExistent_reverts() (gas: 103402)
-L2OutputOracleTest:test_deleteOutputs_multipleOutputs_succeeds() (gas: 286560)
-L2OutputOracleTest:test_deleteOutputs_singleOutput_succeeds() (gas: 172876)
+L2OutputOracleTest:test_deleteL2Outputs_nonExistent_reverts() (gas: 107292)
+L2OutputOracleTest:test_deleteOutputs_multipleOutputs_succeeds() (gas: 302121)
+L2OutputOracleTest:test_deleteOutputs_singleOutput_succeeds() (gas: 180656)
 L2OutputOracleTest:test_getL2OutputIndexAfter_multipleOutputsExist_succeeds() (gas: 267182)
 L2OutputOracleTest:test_getL2OutputIndexAfter_noOutputsExis_reverts() (gas: 17914)
 L2OutputOracleTest:test_getL2OutputIndexAfter_previousBlock_succeeds() (gas: 96086)
@@ -154,7 +154,7 @@ L2OutputOracleTest:test_nextBlockNumber_succeeds() (gas: 17468)
 L2OutputOracleTest:test_proposeL2Output_emptyOutput_reverts() (gas: 26688)
 L2OutputOracleTest:test_proposeL2Output_futureTimetamp_reverts() (gas: 28646)
 L2OutputOracleTest:test_proposeL2Output_notProposer_reverts() (gas: 25782)
-L2OutputOracleTest:test_proposeL2Output_proposeAnotherOutput_succeeds() (gas: 97137)
+L2OutputOracleTest:test_proposeL2Output_proposeAnotherOutput_succeeds() (gas: 101027)
 L2OutputOracleTest:test_proposeL2Output_unexpectedBlockNumber_reverts() (gas: 28402)
 L2OutputOracleTest:test_proposeL2Output_unmatchedBlockhash_reverts() (gas: 29446)
 L2OutputOracleTest:test_proposeL2Output_wrongFork_reverts() (gas: 29005)

packages/contracts-bedrock/contracts/L1/L2OutputOracle.sol

@@ -198,7 +198,7 @@ contract L2OutputOracle is Initializable, Semver {
             );
         }
 
-        emit OutputProposed(_outputRoot, nextOutputIndex(), block.timestamp, _l2BlockNumber);
+        emit OutputProposed(_outputRoot, nextOutputIndex(), _l2BlockNumber, block.timestamp);
 
         l2Outputs.push(
             Types.OutputProposal({

packages/contracts-bedrock/contracts/test/L2OutputOracle.t.sol

@@ -10,6 +10,13 @@ import { Types } from "../libraries/Types.sol";
 contract L2OutputOracleTest is L2OutputOracle_Initializer {
     bytes32 proposedOutput1 = keccak256(abi.encode(1));
 
+    event OutputProposed(
+        bytes32 indexed outputRoot,
+        uint256 indexed l2OutputIndex,
+        uint256 indexed l2BlockNumber,
+        uint256 l1Timestamp
+    );
+
     function setUp() public override {
         super.setUp();
     }
@@ -180,6 +187,7 @@ contract L2OutputOracleTest is L2OutputOracle_Initializer {
     function test_proposeL2Output_proposeAnotherOutput_succeeds() public {
         bytes32 proposedOutput2 = keccak256(abi.encode());
         uint256 nextBlockNumber = oracle.nextBlockNumber();
+        uint256 nextOutputIndex = oracle.nextOutputIndex();
         warpToProposeTime(nextBlockNumber);
         uint256 proposedNumber = oracle.latestBlockNumber();
 
@@ -187,6 +195,10 @@ contract L2OutputOracleTest is L2OutputOracle_Initializer {
         assertEq(nextBlockNumber, proposedNumber + submissionInterval);
 
         vm.roll(nextBlockNumber + 1);
+
+        vm.expectEmit(true, true, true, true);
+        emit OutputProposed(proposedOutput2, nextOutputIndex, nextBlockNumber, block.timestamp);
+
         vm.prank(proposer);
         oracle.proposeL2Output(proposedOutput2, nextBlockNumber, 0, 0);
     }