Need file path check for saving ML model

## Motivation

If we use backend API directly, it can be override a system file.
For example

```
client = DruckerDashClient(logger=logger, host=host)
response = client.run_upload("../../tmp/NEW_FILE", bytes('uploaded!!!!\n', 'utf-8'))
print(response)
```

## Goal
- Check filepath

## Implementation
- implement a path checker
- testing
