[BUGFIX] Fix variables to use css variables

Resources/Public/Sass/Bootstrap5/_sg-jobs.scss

 .dropzone {
-    border-color: $danger;
-    border-radius: $border-radius;
+    border-color: var(--bs-form-invalid-border-color);
+    border-radius: var(--bs-border-radius);
     border-style: dashed;
 
     &.dz-started {
-        border-color: $success;
+        border-color: var(--bs-form-valid-border-color);
     }
 
     .dz-message {