feat(material/checkbox): show background-color in print stylesheet (#22298)

* added color-adjust for checkbox background-color

Author: felhag

src/material/checkbox/checkbox.scss

@@ -288,6 +288,10 @@ $_mat-checkbox-mark-stroke-size: 2 / 15 * checkbox-common.$size !default;
     variables.$linear-out-slow-in-timing-function, opacity checkbox-common.$transition-duration
     variables.$linear-out-slow-in-timing-function;
 
+  // force browser to show background-color when using the print function
+  -webkit-print-color-adjust: exact;
+  color-adjust: exact;
+
   ._mat-animation-noopable & {
     transition: none;
   }