fix(plugin-workflow): fix variable level in filter

[mytharcher]

This is a ...

• New feature
• Improvement
• Bug fix
• Others

Motivation

Description

Related issues

Showcase

Changelog

Language	Changelog
🇺🇸 English	Fixed the issue where variables nested deeper than three levels cannot be used in workflow query node conditions
🇨🇳 Chinese	修复工作流查询节点条件中无法使用超过三层变量的问题

Docs

Language	Link
🇺🇸 English
🇨🇳 Chinese

Checklists

• All changes have been self-tested and work as expected
• Test cases are updated/provided or not needed
• Doc is updated/provided or not needed
• If documentation was changed, the corresponding files in all other languages have been updated to keep them in sync (or this change does not affect docs)
• Component demo is updated/provided or not needed
• Changelog is provided or not needed
• Request a code review if it is necessary