Fix for party members missing from header after viewing private messages / inbox / PMs (#11912)

* Fix bug in missing party members in app header

* Modified by running lint

* Change code for handling missing party members in app header from within computed hiddenHeader property to watcher function on hiddenHeader

Co-authored-by: osiris <eynsan@yahoo.co.uk>

website/client/src/components/header/index.vue

@@ -30,6 +30,7 @@
       </div>
       <div
         v-if="hasParty"
+        ref="partyMembersDiv"
         v-resize="1500"
         class="party-members d-flex"
         @resized="setPartyMembersWidth($event)"
@@ -153,6 +154,15 @@ export default {
       inviteModalGroupType: undefined,
     };
   },
+  watch: {
+    hideHeader () {
+      this.$nextTick(() => {
+        if (this.$refs.partyMembersDiv) {
+          this.setPartyMembersWidth({ width: this.$refs.partyMembersDiv.clientWidth });
+        }
+      });
+    },
+  },
   computed: {
     ...mapGetters({
       user: 'user:data',