Do not package Python library for OpenMLDB Spark distribution

Now the pacakge command will package Python files which make release file large.

```
./dev/make-distribution.sh --name openmldbspark --tgz -Phadoop-2.7 -Pyarn -Pallinone
```

The issue points to the distribution script at `./dev/make-distribution.sh`. Examine this script to understand how Python files are included in the packaging. Look for sections that handle Python dependencies or packaging steps. The goal is to modify the script to exclude Python library files, reducing the final release tarball size. Test by running the provided command and verifying the output size.

Written by the indexing model from the issue text.