Summary

There is no need to sum zero amount token's value in loop, especially each action will call external contract

Vulnerability Details

function getAccountCollateralValue(address user) public view returns (uint256 totalCollateralValueInUsd) {
// loop through each collateral token, get the amount they have deposited, and map it to
// the price, to get the USD value
for (uint256 i = 0; i < s_collateralTokens.length; i++) {
address token = s_collateralTokens[i];
uint256 amount = s_collateralDeposited[user][token];
totalCollateralValueInUsd += getUsdValue(token, amount);
}
return totalCollateralValueInUsd;
}

function getUsdValue(address token, uint256 amount) public view returns (uint256) {
    AggregatorV3Interface priceFeed = AggregatorV3Interface(s_priceFeeds[token]);
    (, int256 price,,,) = priceFeed.staleCheckLatestRoundData();
    // 1 ETH = $1000
    // The returned value from CL will be 1000 * 1e8
    return ((uint256(price) * ADDITIONAL_FEED_PRECISION) * amount) / PRECISION;
}

if the amount is zero, totalCollateralValueInUsd is no need to do the action of getUsdValue.

Impact

cost more gas

Tools Used

Recommendations

One method is to change getAccountCollateralValue function as below:
function getAccountCollateralValue(address user) public view returns (uint256 totalCollateralValueInUsd) {
// loop through each collateral token, get the amount they have deposited, and map it to
// the price, to get the USD value
for (uint256 i = 0; i < s_collateralTokens.length; i++) {
address token = s_collateralTokens[i];
uint256 amount = s_collateralDeposited[user][token];
if(amount>0){
totalCollateralValueInUsd += getUsdValue(token, amount);
}

    }
    return totalCollateralValueInUsd;
}

The another method is to change getUsdValue function as below:
function getUsdValue(address token, uint256 amount) public view returns (uint256) {
if(amount==0)
return 0;
AggregatorV3Interface priceFeed = AggregatorV3Interface(s_priceFeeds[token]);
(, int256 price,,,) = priceFeed.staleCheckLatestRoundData();
// 1 ETH = $1000
// The returned value from CL will be 1000 * 1e8
return ((uint256(price) * ADDITIONAL_FEED_PRECISION) * amount) / PRECISION;
}