[FIX-25636] fix: re-enable schema previsualization for Trino/Presto t…

…able/schemas

This patch fixes failures occuring when performing a schema preview of a
Presto table.

The `PrestoBaseEngineSpec.where_latest_partition` attempts to construct
SQLAlchemy `Column` objects based on a name and a type. However, this leads
to the following error in our case:

```console
sqlalchemy.exc.ArgumentError: 'SchemaItem' object, such as a 'Column' or a 'Constraint' expected, got 'VARCHAR'
```

This comes from the fact that we run `Column('column_name', 'VARCHAR')` instead of
`Column('column_name', sqlalchemy.types.VARCHAR)`. We fix this particular error by
passing the _actual_ type class, and not just a string.

> [!NOTE]
> This also fixes the same issue for Trino tables, as `TrinoEngineSpec` inherits
> from `PrestoBaseEngineSpec`, the Presto db client class.

Fixes #25962
Fixes #25962

superset/db_engine_specs/presto.py

@@ -507,7 +507,10 @@ def where_latest_partition(  # pylint: disable=too-many-arguments
         }
 
         for col_name, value in zip(col_names, values):
-            col_type = column_type_by_name.get(col_name)
+            col_type = None
+            if col_type_name := column_type_by_name.get(col_name):
+                if col_type_class := getattr(types, col_type_name, None):
+                    col_type = col_type_class()
 
             if isinstance(col_type, types.DATE):
                 col_type = Date()

tests/unit_tests/db_engine_specs/test_presto.py

@@ -115,10 +115,10 @@ def test_get_schema_from_engine_params() -> None:
 @pytest.mark.parametrize(
     ["column_type", "column_value", "expected_value"],
     [
-        (types.DATE(), "2023-05-01", "DATE '2023-05-01'"),
-        (types.TIMESTAMP(), "2023-05-01", "TIMESTAMP '2023-05-01'"),
-        (types.VARCHAR(), "2023-05-01", "'2023-05-01'"),
-        (types.INT(), 1234, "1234"),
+        ("DATE", "2023-05-01", "DATE '2023-05-01'"),
+        ("TIMESTAMP", "2023-05-01", "TIMESTAMP '2023-05-01'"),
+        ("VARCHAR", "2023-05-01", "'2023-05-01'"),
+        ("INT", 1234, "1234"),
     ],
 )
 def test_where_latest_partition(