Remove entity_operation_alter hooks

Problem/Motivation

Our entity_operation_alter (one in each integration sub-module: display_builder_entity_view, display_builder_page_layout, display_builder_views) are not needed since we have harmonized the discovery and the interface of "buildables" as plugins in #3549266: Move DisplayBuildableInterface to a new plugin type.

And they will be even less relevant once we will be able to execute Instance::get('buildable')::getUrlFromInstanceId() and Instance::get('buildable')::getDisplayUrlFromInstanceId() once #3562989: Implements RevisionLogInterface for Instance entity will be merged.

Because we don't need to delegate to each sub-module a logic which is already the same each time.

Proposed resolution

Remove the hooks.