Backport color-adjust for v4

Keeps checkboxes, radios, and switches with their intended design when printing.

Backports #29714

scss/_custom-forms.scss

@@ -13,6 +13,7 @@
   display: block;
   min-height: $font-size-base * $line-height-base;
   padding-left: $custom-control-gutter + $custom-control-indicator-size;
+  color-adjust: exact; // Keep themed appearance for print
 }
 
 .custom-control-inline {