fix problem with you-are-missing message and refactor other messages in onboard meeting

src/views/OnboardMeetingMembersView.vue

@@ -8,15 +8,6 @@
       Meeting Members
     </h1>
 
-    <!-- Back Button -->
-    <button
-      @click="$router.back()"
-      class="mb-6 flex items-center text-blue-600 hover:text-blue-800"
-    >
-      <fa icon="arrow-left" class="mr-2" />
-      Back to Meetings
-    </button>
-
     <!-- Error State -->
     <div v-if="errorMessage">
       <div class="text-center text-red-600 py-8">