tests: use fixture to clear sqlmodel between tests

These tests share the same structure and field names, so
they conflict if not cleaned up.

Author: spazm

tests/test_field_sa_column.py

@@ -5,7 +5,7 @@
 from sqlmodel import Field, SQLModel
 
 
-def test_sa_column_takes_precedence() -> None:
+def test_sa_column_takes_precedence(clear_sqlmodel) -> None:
     class Item(SQLModel, table=True):
         id: Optional[int] = Field(
             default=None,

tests/test_field_sa_column_mapped_column.py

@@ -6,7 +6,7 @@
 from sqlmodel import Field, SQLModel
 
 
-def test_sa_column_takes_precedence() -> None:
+def test_sa_column_takes_precedence(clear_sqlmodel) -> None:
     class Item(SQLModel, table=True):
         id: Optional[int] = Field(
             default=None,