PPML: add gramine spark/pyspark ut workflow

[ShanSimu]

Description

add gramine unit tests workflow

1. Why the change?

2. User API changes

3. Summary of the change

4. How to test?

• [ ] N/A
• [ ] Unit test
• [ ] Application test
• [ ] Document test
• [ ] ...

5. New dependencies

• [ ] New Python dependencies - Dependency1 - Dependency2 - ...
• [ ] New Java/Scala dependencies and their license - Dependency1 and license1 - Dependency2 and license2 - ...