🐛 fix broken image upload button (#766)
🐛 fix broken image upload button (#766)

closes https://github.com/TryGhost/Ghost/issues/8637
- add a default object to `_openImageFileDialog` args so that destructuring with default params works when not passed a value
acburdine/Ghost-Admin,TryGhost/Ghost-Admin,TryGhost/Ghost-Admin,acburdine/Ghost-Admin,kevinansfield/Ghost-Admin,kevinansfield/Ghost-Admin