Fixes #20730.
This change computes the minimum needed height of what a single line of text would be for the custom checkboxes/radios. This is required because our custom control indicators are positioned absolutely, meaning they cannot be clearfixed or anything like that. Using a computed value means it should scale nicely in case of customization
.custom-control {
position: relative;
display: inline-block;
+ min-height: (1rem * $line-height-base);
padding-left: $custom-control-gutter;
cursor: pointer;