Close remote project windows when leaving a call

crates/project/src/project.rs

@@ -175,6 +175,7 @@ pub enum Event {
     },
     RemoteIdChanged(Option<u64>),
     DisconnectedFromHost,
+    Closed,
     CollaboratorUpdated {
         old_peer_id: proto::PeerId,
         new_peer_id: proto::PeerId,
@@ -1172,6 +1173,10 @@ impl Project {
         }
     }
 
+    pub fn close(&mut self, cx: &mut ModelContext<Self>) {
+        cx.emit(Event::Closed);
+    }
+
     pub fn is_read_only(&self) -> bool {
         match &self.client_state {
             Some(ProjectClientState::Remote {