Introduce posibility to disable !important suffix for utility classes (#29625)

scss/_variables.scss

@@ -227,6 +227,7 @@ $enable-pointer-cursor-for-buttons:           true !default;
 $enable-rfs:                                  true !default;
 $enable-validation-icons:                     true !default;
 $enable-deprecation-messages:                 true !default;
+$enable-important-utilities:                  true !default;
 
 
 // Spacing

scss/mixins/_utilities.scss

@@ -28,7 +28,7 @@
     .#{$property-class + $infix + $property-class-modifier} {
       @each $property in $properties {
         // stylelint-disable-next-line declaration-no-important
-        #{$property}: $value !important;
+        #{$property}: $value if($enable-important-utilities, !important, null);
       }
     }
   }