pamhyr: Close study DB if already init.

src/Model/Tools/PamhyrDB.py

@@ -35,8 +35,10 @@ class SQLModel(SQL):
     _sub_classes = []
 
     def _init_db_file(self, db, is_new=True):
-        exists = Path(db).exists()
+        if self._db is not None:
+            self._db.close()
 
+        exists = Path(db).exists()
         if exists and is_new:
             os.remove(db)