Revert "added uniqueness constraint to human task so it cannot have multiple human tasks for a process instance and task id w/ burnettk (#396)"

This reverts commit 9b199cad71.

spiffworkflow-backend/migrations/versions/56e17aab85ca_.py

@@ -1,32 +0,0 @@
-"""empty message
-
-Revision ID: 56e17aab85ca
-Revises: 64adf34a98db
-Create Date: 2023-07-14 11:54:20.187703
-
-"""
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision = '56e17aab85ca'
-down_revision = '64adf34a98db'
-branch_labels = None
-depends_on = None
-
-
-def upgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    with op.batch_alter_table('human_task', schema=None) as batch_op:
-        batch_op.create_unique_constraint('process_instance_task_unique', ['process_instance_id', 'task_id'])
-
-    # ### end Alembic commands ###
-
-
-def downgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    with op.batch_alter_table('human_task', schema=None) as batch_op:
-        batch_op.drop_constraint('process_instance_task_unique', type_='unique')
-
-    # ### end Alembic commands ###

spiffworkflow-backend/src/spiffworkflow_backend/models/human_task.py

@@ -23,14 +23,6 @@ if TYPE_CHECKING:
 class HumanTaskModel(SpiffworkflowBaseDBModel):
     __tablename__ = "human_task"
 
-    __table_args__ = (
-        db.UniqueConstraint(
-            "process_instance_id",
-            "task_id",
-            name="process_instance_task_unique",
-        ),
-    )
-
     id: int = db.Column(db.Integer, primary_key=True)
     process_instance_id: int = db.Column(
         ForeignKey(ProcessInstanceModel.id), nullable=False, index=True  # type: ignore