Fix possible errors

mautrix_telegram/bot.py

@@ -65,6 +65,12 @@ class Bot(AbstractUser):
             except (ChannelPrivateError, ChannelInvalidError):
                 self.remove_chat(id.channel_id)
 
+    def register_portal(self, portal):
+        self.add_chat(portal.tgid, portal.peer_type)
+
+    def unregister_portal(self, portal):
+        self.remove_chat(portal.tgid)
+
     def add_chat(self, id, type):
         if id not in self.chats:
             self.chats[id] = type

mautrix_telegram/portal.py

@@ -491,8 +491,11 @@ class Portal:
         if self.peer_type == "user":
             await self.main_intent.leave_room(self.mxid)
             self.delete()
-            del self.by_tgid[self.tgid_full]
-            del self.by_mxid[self.mxid]
+            try:
+                del self.by_tgid[self.tgid_full]
+                del self.by_mxid[self.mxid]
+            except KeyError:
+                pass
         elif source and source.tgid != user.tgid:
             if self.peer_type == "chat":
                 await source.client(DeleteChatUserRequest(chat_id=self.tgid, user_id=user.tgid))