Fix: Replace StrEnum with strenum in code_exec.py (#9376)
### What problem does this PR solve?
- The enum import was changed from Python's built-in StrEnum to the
strenum package.
- Fix error `Warning: Failed to import module code_exec: cannot import
name 'StrEnum' from 'enum' (/usr/lib/python3.10/enum.py)`
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
#9082#6365
<u> **WARNING: it's not compatible with the older version of `Agent`
module, which means that `Agent` from older versions can not work
anymore.**</u>
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
Yongteng Lei
Kevin Hu
Liu An