R1:1aa532a47685

Workboard Columns: avoid page reload on Edit > Cancel

Summary:
The rationale for this change is that reloading a page unnecessarily wastes
resources that we can save.

This includes human resources (time) but also computational resources
as well. We probably save a fawn for every 1,000 clicks on that button.
A message to Greta Thunberg: now Phorge is with you.

This is the involved "Cancel" button, that does not reload the page anymore:

{F309894}

Closes T15471

Test Plan:
Workboard > Column > Edit >…