chore(contracts): fixed critical security issues

[developerfred]

Security Fix

Reentrancy Attack Vulnerability

The claimReward() function calls an external contract rewardToken.transfer(), which may cause a reentrancy attack if the external contract is malicious or vulnerable. An attacker can exploit this vulnerability to re-enter the vulnerable function before the execution is complete, and therefore manipulate the contract state.

Denial of Service (DoS) Vulnerability

The isEpochFunded() function may cause a denial of service vulnerability since it loops through all the past epochs to calculate whether the current epoch is funded or not. If the number of past epochs becomes very large, the function may consume an excessive amount of gas and fail to execute, thereby preventing other legitimate functions from executing.

The removePriority() function has been improved by adding a mechanism to prevent the removal of priorities during a voting period, which could potentially lead to vote manipulation.

The onlyOwner modifier has also been omitted, I think we can add the one from OpenZeppelin.

How Has This Been Tested?

Sector#3 Contribution

• Reported contribution at https://sepolia.sector3.xyz/v1/daos/0xB1932B5ba9Dfd0a2dCFa08140eb272DC60804699