2 mysterious fatal errors with Views

Problem/Motivation

As a follow-up of #3534215: Implement WithDisplayBuilderInterface in Views, we have 2 issues left:

• On the rendered view : Call to a member function getOption(), sometimes, when we use the UIP2 ViewRows instead of the DB one: may be related to #3533044: Merge the two ViewRowsSource plugins and the issue may be addressed in UI Patterns 2 level
• On the display builder (ViewsController::getBuidler()): MissingMandatoryParametersException, sometimes, when we change the display builder profile in the display extender admin UI without saving the view. Other unsaved changes in the view are OK

Proposed resolution

First, try to guess why we sometimes have those issues, sometimes not.

Then fix :)