Agreements : On duplicating an agreement the "General notes about this agreement's license" field should be copied

On duplicating an agreement the "General notes about this agreement's license" field should be copied when the user selects to duplicate "Linked Licenses".

Step to reproduce:
1. Edit an agreement and link a license to it.
2. Add test to the field "General notes about this agreement's license"
3. Save the Agreement
4. Select the option "Duplicate" in the agreement header
5. In the duplication modal check the "Linked licenses" option
6. Select "Save & close"

The duplicated agreement field "General notes about this agreement's license" is empty.