Alternate fix to #19006: Add a single variable for controlling that inner 1px padding on .popover

Author: mdo

scss/_popover.scss

@@ -5,7 +5,7 @@
   z-index: $zindex-popover;
   display: block;
   max-width: $popover-max-width;
-  padding: 1px;
+  padding: $popover-inner-padding;
   // Our parent element can be arbitrary since tooltips are by default inserted as a sibling of their target element.
   // So reset our font and text properties to avoid inheriting weird values.
   @include reset-text();

scss/_variables.scss

@@ -606,6 +606,7 @@ $tooltip-arrow-color:         $tooltip-bg !default;
 
 // Popovers
 
+$popover-inner-padding:               1px !default;
 $popover-bg:                          #fff !default;
 $popover-max-width:                   276px !default;
 $popover-border-width:                $border-width !default;