Custom tickets: Optional oneOf and manyOf should have an ability to clear all values

[Amantini1997]

Description

As it stands, with the front end UI, if you have selected a value on oneOf (or at least one of manyOf) property, there's no way to remove it.

We should allow the user to clear the values as long as it's not a required field (perhaps by adding a X icon? consult with our in house design expert if necessary).

Note we should also be able to do this with special rendered ones, like jobsAndUsers:

Goals

• Make it possible to clear the value of oneOf properties (where allowed);
• Make it easier to clear the value of manyOf properties (where allowed);

Tasks

• Add a button to clear the value of any select input if allowed by the property (i.e. not required)

Product Link

https://github.com/3drepo/3D-Repo-Product-Team/issues/461