BUG #14245: Fixed incorrect default values for range-domains.

vtkSMRangeDomainTemplate::Update() was not setting up the domain value correctly
when the required property was a single vector-property. That was resulting in
the logic to set default values getting confused, resulting in incorrect
defaults for properties (as manifested in the BUG #14245). This fixes that
isssue.

Change-Id: I751476ab3683dfae77101d1277cc1f2ec145ad78
Merge topic '14245_fix_default_values' into next

141a698 BUG #14245: Fixed incorrect default values for range-domains.