Acknowledge channel notes and chat changes when views are active

Co-authored-by: Mikayla <mikayla@zed.dev>

crates/collab/src/tests/channel_buffer_tests.rs

@@ -445,8 +445,8 @@ fn channel(id: u64, name: &'static str) -> Channel {
     Channel {
         id,
         name: name.to_string(),
-        has_note_changed: false,
-        has_new_messages: false,
+        unseen_note_version: None,
+        unseen_message_id: None,
     }
 }