Call plugin unload function after stopping event loop (#539)

This can prevent race conditions where unload is clearing data but main is still working with it

backend/decky_loader/plugin/sandboxed_plugin.py

@@ -115,11 +115,11 @@ class SandboxedPlugin:
 
         if "stop" in data:
             self.log.info("Calling Loader unload function.")
-            await self._unload()
             get_event_loop().stop()
             while get_event_loop().is_running():
                 await sleep(0)
             get_event_loop().close()
+            await self._unload()
             raise Exception("Closing message listener")
 
         d: SocketResponseDict = {"res": None, "success": True, "id": data["id"]}