Re-introduce entityId and entityType into drupalSettings.canvas

Overview

in ✨ Move entity type and ID from base path and into routing parameters Active , one of the things that happened is the removal of drupalSettings.canvas.entityType and drupalSettings.canvas.entityId. For extensions, these 2 values are pretty useful.

For the Acquia Content Optimization, we've been detecting the entity and entity type in javascript using these 2 variables. After upgrading to RC1, we can't do that anymore.

There are alternatives using the windows.location, but I think it's cleaner to use the previous variables.

Proposed resolution

Re-introduce the same variables.

User interface changes