Bug 1826285: Remove the focus color on inputs in the "Modern" theme

behatnotneeded

Change-Id: I701ea58238a8ac4789b55101c81f92dfcc30003a

htdocs/theme/modern/sass/form/_form.scss

 .form-control:focus {
     box-shadow: inset 0 0px 0px rgba(0,0,0,1);
-    background-color: scale-color($theme-secondary-color, $lightness: 65%);
 }
 
 form#filter {

htdocs/theme/modern/sass/utilities/_bootstrap-variables.scss

@@ -26,7 +26,6 @@ $input-color:                               $gray-500;
 $input-border-color:                        #ccc;
 
 $input-focus-border-color:                  $theme-accent-color;
-$input-focus-bg:                            scale-color($theme-accent-color, $lightness: 60%);
 
 $input-placeholder-color:                   #999;