feat: Improve the initial screen placeholder (#7708)

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

app/javascript/dashboard/components/widgets/conversation/EmptyState/EmptyStateMessage.vue

@@ -0,0 +1,33 @@
+<template>
+  <div class="flex flex-col items-center justify-center h-full">
+    <img
+      class="m-4 w-32 hidden dark:block"
+      src="~dashboard/assets/images/no-chat-dark.svg"
+      alt="No Chat dark"
+    />
+    <img
+      class="m-4 w-32 block dark:hidden"
+      src="~dashboard/assets/images/no-chat.svg"
+      alt="No Chat"
+    />
+    <span
+      class="text-sm text-slate-800 dark:text-slate-200 font-medium text-center"
+    >
+      {{ message }}
+      <br />
+    </span>
+    <!-- Cmd bar, keyboard shortcuts placeholder -->
+    <feature-placeholder />
+  </div>
+</template>
+
+<script>
+export default {
+  props: {
+    message: {
+      type: String,
+      required: true,
+    },
+  },
+};
+</script>