feat: Support Dark mode for the widget (#4137)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/javascript/shared/components/DateSeparator.vue

@@ -1,12 +1,18 @@
 <template>
-  <div class="date--separator">
+  <div
+    class="date--separator"
+    :class="$dm('text-slate-700', 'dark:text-slate-200')"
+  >
     {{ formattedDate }}
   </div>
 </template>
 
 <script>
 import { formatDate } from 'shared/helpers/DateHelper';
+import darkModeMixin from 'widget/mixins/darkModeMixin.js';
+
 export default {
+  mixins: [darkModeMixin],
   props: {
     date: {
       type: String,
@@ -30,7 +36,6 @@ export default {
 
 .date--separator {
   font-size: $font-size-default;
-  color: $color-body;
   height: 50px;
   line-height: 50px;
   position: relative;