## What changes were proposed in this pull request?
Expose numPartitions (expert) param of PySpark FPGrowth.
## How was this patch tested?
+ [x] Pass all unit tests.
Author: Yan Facai (颜发才) <facai.yan@gmail.com>
Closes#18058 from facaiy/ENH/pyspark_fpg_add_num_partition.
## What changes were proposed in this pull request?
Follow-up for #17218, some minor fix for PySpark ```FPGrowth```.
## How was this patch tested?
Existing UT.
Author: Yanbo Liang <ybliang8@gmail.com>
Closes#18089 from yanboliang/spark-19281.
## What changes were proposed in this pull request?
- Add `HasSupport` and `HasConfidence` `Params`.
- Add new module `pyspark.ml.fpm`.
- Add `FPGrowth` / `FPGrowthModel` wrappers.
- Provide tests for new features.
## How was this patch tested?
Unit tests.
Author: zero323 <zero323@users.noreply.github.com>
Closes#17218 from zero323/SPARK-19281.
