fix: useFormApi in strictMode with react 18

packages/semi-ui/form/baseForm.tsx

@@ -151,7 +151,7 @@ class Form extends BaseComponent<BaseFormProps, BaseFormState> {
 
     componentWillUnmount() {
         this.foundation.destroy();
-        this.formApi = null;
+        // this.formApi = null;
     }
 
     get adapter(): BaseFormAdapter<BaseFormProps, BaseFormState> {