### What problem does this PR solve?
- [x] New Feature (non-breaking change which adds functionality)
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Co-authored-by: Yingfeng <yingfeng.zhang@gmail.com>
Co-authored-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
feat: Add DynamicInputVariable to RetrievalForm #1739
### Type of change
- [x] New Feature (non-breaking change which adds functionality)