fix: v4 ui issues (#10652)

This PR has the following fixes

1. Remove leading `:` in inbox view push message content
2. Styles for block quotes in text
3. Better condition for checking bot message
4. Use dompurify

app/javascript/dashboard/components-next/Inbox/InboxCard.vue

@@ -80,6 +80,10 @@ const messageClasses = computed(() => ({
 }));
 
 const formatPushMessage = message => {
+  if (message.startsWith(': ')) {
+    return message.slice(2);
+  }
+
   return message.replace(/^([^:]+):/g, (match, name) => {
     return `<span class="${messageClasses.value.emphasis}">${name}:</span>`;
   });