Add step size to SQAParameter class (#5212)

Summary:
Pull Request resolved: #5212

Just adds the field to the SQAParameter class to help with testing. The remaining plumbing will be done as part of the diff that adds the attribute to the RangeParameter class.

Reviewed By: dme65

Differential Revision: D107108021

fbshipit-source-id: 0acc2c0cf65aca85e45c73f7a4244fadba97f215

Author: saitcakmak

ax/storage/sqa_store/sqa_classes.py

@@ -102,6 +102,7 @@ class SQAParameter(Base):
 
     # Attributes for Range Parameters
     digits: Mapped[int | None] = Column(Integer)
+    step_size: Mapped[float | None] = Column(Float)
     log_scale: Mapped[bool | None] = Column(Boolean)
     lower: Mapped[Decimal | None] = Column(Float)
     upper: Mapped[Decimal | None] = Column(Float)