🐛(frontend) fix Crisp chatbot CSS override covering room actions

Fix regression where Crisp chatbot CSS changes caused their button to
cover useful room actions due to failing CSS override rules.

Updates CSS specificity and positioning to ensure Crisp chat button
doesn't interfere with room functionality while maintaining chatbot
accessibility for user support.

src/frontend/src/styles/index.css

@@ -25,7 +25,7 @@ body,
   }
 }
 
-body:has(.lk-video-conference) #crisp-chatbox > div > a {
+body:has(.lk-video-conference) #crisp-chatbox-button {
   display: none !important;
 }