Completing Party role is removed even if the addition of a different completing party is cancelled

[forgeuxGH5]

Steps to reproduce
Add an individual as a completing party
Add another individual or business - select completing party but Cancel the form or deselect completing party in the form

See that the original persons completing party role has been removed

Expected behaviour
The first person's completing party role should be retained if the addition of a different completing party is cancelled.

[ser-popov]

will check tomorrow on a fresh build