Impact Category Duplication Fixes

[mrvisscher]

Some of the fixes @marc-vdm mentioned in #1164

• Comma's are now accepted during IC duplication
• At least one field must be filled during IC duplication, or the button is disabled

I wouldn't close the issue as there's still a lot to fix about IC duplication, but this at least makes it a little better in time for the next release.

Checklist

• [x] Keep pull requests small so they can be easily reviewed.
• [x] Update the documentation, please follow the numpy style guide.
• [ ] Update tests.
• [x] Categorize the PR by setting a good title and adding one of the labels: bug, feature, ui, change, documentation, breaking, ci as they show up in the changelog.
• [x] Link this PR to related issues by using closing keywords.
• [x] Request a review from another developer.

[coveralls]

coverage: 50.392% (+0.06%) from 50.33% when pulling b9a89b24962cf45de5c28865bca1947219eb0da1 on mrvisscher:ic-duplication-fixes into 51566ac32c80bbc40d4f976084dbb1a8ee88f985 on LCA-ActivityBrowser:master.