Fix flet pack command

Fix #1552

Author: FeodorFitsner

sdk/python/packages/flet/src/flet/__pyinstaller/utils.py

@@ -4,7 +4,7 @@
 from distutils.dir_util import copy_tree
 from pathlib import Path
 
-from flet.utils import get_package_bin_dir
+from flet_runtime.utils import get_package_bin_dir
 
 
 def get_flet_bin_path():