Add the following code in Customize > Additional CSS:

.class li {
     list-style-type: disc !important;
     list-style-position: inside !important;
     padding-left: XXem !important;
     text-indent: -XXem !important;
}

If it does not work, try replacing em with px or target ul li / ol li instead of just li.

Source: https://stackoverflow.com/questions/33362748/li-item-on-two-lines-second-line-has-no-margin and https://stackoverflow.com/questions/11556493/2nd-line-in-li-start-under-the-bullet-after-css-reset