make CDP debt index always update as long as there is a global index update

[rayeaster]

fix as suggested by @dmitriia https://github.com/cantinasec/review-badgerdao/issues/44#issuecomment-1751718447

[dmitriia]

It looks like it is always _cdp.debt == _newDebt, _cdp.coll == _newColl for the event:

    function _emitCdpUpdatedEventForSyncAccounting(
        bytes32 _cdpId,
        Cdp storage _cdp,
        uint256 _newDebt,
        uint256 _newColl
    ) internal {
        emit CdpUpdated(
            _cdpId,
            ISortedCdps(sortedCdps).getOwnerAddress(_cdpId),
            msg.sender,
>           _cdp.debt,
>           _cdp.coll,
>           _newDebt,
>           _newColl,
            _cdp.stake,
            CdpOperation.syncAccounting
        );
    }

For collateral part it is needed to have old one returned or it can be just said that CdpFeeSplitApplied is enough for reporting.

For debt the order can be changed:

https://github.com/Badger-Finance/ebtc/blob/c8b1f4b6d390983b37e0d52a3ea8e44efb07acd6/packages/contracts/contracts/CdpManagerStorage.sol#L354-L360

            if (prevDebt != _newDebt) {
                {
                    // Apply pending debt redistribution to this CDP
-                   _cdp.debt = _newDebt;
                    _emitCdpUpdatedEventForSyncAccounting(_cdpId, _cdp, _newDebt, _cdp.coll);
+                   _cdp.debt = _newDebt;
                }
            }

[dapp-whisperer]

optimistic merging as per thread