acp: Update to 0.0.30 (#36643)

See: https://github.com/zed-industries/agent-client-protocol/pull/20

Release Notes:

- N/A

crates/agent2/src/thread.rs

@@ -2248,7 +2248,7 @@ impl ThreadEventStream {
 
     fn send_canceled(&self) {
         self.0
-            .unbounded_send(Ok(ThreadEvent::Stop(acp::StopReason::Canceled)))
+            .unbounded_send(Ok(ThreadEvent::Stop(acp::StopReason::Cancelled)))
             .ok();
     }