Joiner: When number of Partition field has value, the output has no difference with and without value in Number of partition field.

After successful pipeline from File->Joiner->File, 196 blank files are generated along with 4 records of 4 different files with one record in each file in output folder. Total 200 files are created, 196 blank files and 4 data files with and without value in Number of Partitions.

Steps to reproduce:

1. Launch the latest CDAP (6.8.0)

2. Open File source, Joiner plugin and File sink, now establish the connection from source to analytics to sink (File source->Joiner->File sink). Fill the properties and click on validate.

3. Preview the pipeline, it is successful, records are shown in preview data.

4. Now deploy the pipeline. The pipeline gets succeeded.

5. Verify the files generated in output folder path, 4 files are generated with each Joiner record in each file and also 196 blank files are generated.

Expected: Pipeline should be successful and single file should be generated with all the Joiner functionality records from input table and blank files should not be generated as partition is not used.
Actual: 4 different files with Joiner record in each file and 196 blank files created in output folder path.