[BUG] duplicate signatures

[undefined-moe]

Describe the bug
duplicate cla signatures

• feat(ui): add visual drag-drop editor for training management page hydro-dev/Hydro#1115
• hydro-dev/Hydro@37d9b25

To Reproduce

• Create a pull request
• Send sign cla comment
• Setup contributor-assistant workflow
• Send another sign cla comment
• Get a duplicate

Expected behavior
Should pick only one of them