Drop wrong import from CSV import in frontend

aleksis/apps/lesrooster/frontend/components/CSVAdditionalParams.vue

 <script>
-import additionalParamsMixin from "aleksis.apps.csv_import/mixins/additionalParamsMixin.js";
 import { validityRangeById } from "./additionalParams.graphql";
 
 export default {
   name: "CSVAdditionalParams",
-  mixins: [additionalParamsMixin],
+  props: {
+    /**
+     * The current additional params
+     */
+    additionalParams: {
+      type: Object,
+      required: true,
+    },
+  },
   apollo: {
     validityRange: {
       query: validityRangeById,