Generalize meta_path json file creation in load.py [#4540]
# What does this PR do?

## Summary

*In function `_copy_script_and_other_resources_in_importable_dir`, using string split when generating `meta_path` throws error in the edge case raised in #4540.*

## Additions
-

## Changes
- Changed meta_path to use `os.path.splitext` instead of using `str.split` to generalize code.

## Deletions
-
## Issues Addressed : 

Fixes #4540