refactor: Optimize parameter conversion for get_api_detail func

[lvxinyu-1117]

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en: Optimize parameter conversion for get_api_detail func
zh(optional): 优化plugin节点获取变量接口的类型转换函数

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 77.14286% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
backend/application/workflow/workflow.go	75.00%	5 Missing and 3 partials ⚠️

Files with missing lines	Coverage Δ
backend/crossdomain/impl/plugin/plugin.go	43.92% <100.00%> (ø)
backend/application/workflow/workflow.go	48.31% <75.00%> (ø)

... and 1874 files with indirect coverage changes

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