Try this. I’m on mobile so I can’t open developer tools. Left me know if this works.
body .gform_wrapper .gform_body .gform_fields .gfield .gfield_checkbox li {
float: left;
}
body .gform_wrapper .gform_body .gform_fields .gfield .gfield_checkbox li input[type=checkbox] {
float: left;
}
If this works for you, then when you update to 2.5 remove the li from the code.