When both external and duplicate are added, beep boop removes both labels and resets to open state.

[ChristianMurphy]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)

Steps to reproduce

see: remarkjs/react-markdown#641

Expected behavior

One or both labels should be kept, and phase should move to phase/no

[wooorm]

yeah the thinking is that only one reason exists per a category: semver/major or semver/minor. open/multiple or open/needs-info, no/wontfix or no/external