http-api: T8989: fix routers.py regressions from initial commit

- Restore mask_dict/config_dict variable names in _execute_configure_op
  (shadowing of Config object was causing potential crash on delete ops)
- Fix load_section_tree() call to pass correct 3 arguments
- Pass data.destructive to merge_config() to preserve destructive behavior

Author: omnom62

src/services/api/rest/routers.py

@@ -460,8 +460,8 @@ def _execute_configure_op(
                 section = c.section
 
             elif isinstance(c, BaseConfigSectionTreeModel):
-                mask = c.mask
-                config = c.config
+                mask_dict = c.mask
+                config_dict = c.config
 
             if isinstance(c, BaseConfigureModel):
                 if op == 'set':
@@ -487,9 +487,11 @@ def _execute_configure_op(
 
             elif isinstance(c, BaseConfigSectionTreeModel):
                 if op == 'set':
-                    session.set_section_tree(config)
+                    session.set_section_tree(config_dict)
                 elif op == 'load':
-                    session.load_section_tree(mask, config)
+                    config = Config(session_env=env)
+                    config_tree = config.get_config_tree()
+                    session.load_section_tree(config_tree, mask_dict, config_dict)
                 else:
                     raise op_error
         # end for
@@ -726,7 +728,7 @@ async def config_file_op(data: ConfigFileModel, background_tasks: BackgroundTask
                     case 'load':
                         session.migrate_and_load_config(path)
                     case 'merge':
-                        session.merge_config(path)
+                        session.merge_config(path, destructive=data.destructive)
 
                 config = Config(session_env=env)
                 d = get_config_diff(config)