🐛 Fix unexpected file dialog when pressing <enter> on user screen (#833)
🐛 Fix unexpected file dialog when pressing <enter> on user screen (#833)

closes TryGhost/Ghost#8835
- adds `type="button"` attribute to the file dialog trigger button, the default type for buttons is "submit" which will be triggered by pressing `<enter>` in a form field
TryGhost/Ghost-Admin,kevinansfield/Ghost-Admin,kevinansfield/Ghost-Admin,TryGhost/Ghost-Admin,acburdine/Ghost-Admin,acburdine/Ghost-Admin