Specify Python 3.12 version for Java interop tests

Otherwise the action does nothing and uses the system-installed Python:

```
Run actions/setup-python@0a5c615
Warning: Neither 'python-version' nor 'python-version-file' inputs were supplied. Attempting to find '.python-version' file.
Warning: .python-version doesn't exist.
Warning: The `python-version` input is not set.  The version of Python currently in `PATH` will be used.
```

Signed-off-by: Martin Tzvetanov Grigorov <[email protected]>

Author: martin-g

.github/workflows/test-lang-java.yml

@@ -112,6 +112,8 @@ jobs:
 
       - name: 'Setup Python for Generating Input Data'
         uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
+        with:
+          python-version: '3.12'
 
       - name: 'Apt Install Compression Libs Required by Python'
         run: |