Unable to pass custom properties to CModal

I am trying to migrate from v3 to v4 and have discovered that v4 no longer allows me to pass additional properties to CModal such as `data-testid` which v3 allowed this (see this code https://github.com/coreui/coreui-react/blob/v3/src/modal/CModal.js#L34)

I would like to see this feature brought back as it is essential for my automated test suites to find the modal effectively