Move EE differences for `app/assets/javascripts/diffs/components/diff_line_note_form.vue`

The file app/assets/javascripts/diffs/components/diff_line_note_form.vue has differences between CE and EE.

Diferences

diff --git a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/diffs/components/diff_line_note_form.vue b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/diffs/components/diff_line_note_form.vue
index 18edbe286ba..95fde0e83b9 100644
--- a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/diffs/components/diff_line_note_form.vue
+++ b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/diffs/components/diff_line_note_form.vue
@@ -1,6 +1,7 @@
 <script>
 import { mapState, mapGetters, mapActions } from 'vuex';
 import { s__ } from '~/locale';
+import batchCommentsDiffLineNoteFormMixin from 'ee/batch_comments/mixins/diff_line_note_form';
 import noteForm from '../../notes/components/note_form.vue';
 import autosave from '../../notes/mixins/autosave';
 import { DIFF_NOTE_TYPE } from '../constants';
@@ -9,7 +10,7 @@ export default {
   components: {
     noteForm,
   },
-  mixins: [autosave],
+  mixins: [autosave, batchCommentsDiffLineNoteFormMixin],
   props: {
     diffFileHash: {
       type: String,
@@ -103,6 +104,7 @@ export default {
       :help-page-path="helpPagePath"
       save-button-title="Comment"
       class="diff-comment-form"
+      @handleFormUpdateAddToReview="addToReview"
       @cancelForm="handleCancelCommentForm"
       @handleFormUpdate="handleSaveNote"
     />

What needs to be done

1. Create a CE counterpart of batchCommentsDiffLineNoteFormMixin
2. Create an empty handler for addToReview in that mixin
3. Use ee_else_ce to import the mixin into this file.