Update run_i18n_extract.ts (#44092)

call `process.exit()` on `i18n_extact` complete. this ensures the process closes when spawned from a child process.

src/dev/run_i18n_extract.ts

@@ -88,6 +88,7 @@ run(
         log.error(error);
       }
     }
+    process.exit();
   },
   {
     flags: {