fix: use connection context in load_preprocessed_projects to resolve pandas engine warnings

Data/database/sql_connector.py

@@ -56,10 +56,11 @@ def load_preprocessed_projects():
         FROM PreProcessed_Projects
         """
 
-        df = pd.read_sql(
-            query,
-            engine
-        )
+        with engine.connect() as conn:
+            df = pd.read_sql(
+                query,
+                conn
+            )
 
         if "features" in df.columns: