Faulty access check on "Save and manage content"

Problem/Motivation

In rocketship_core_form_node_form_alter() the visibility of the Save and manage content button for existing nodes is checked by checking access on the route.

This doesn't work if you install e.g. Entity 404 → or Untranslated 404 → 2.x (which uses the same concept of access checking), because you might be creating a new translation (causing the route to be inaccessible).

Steps to reproduce

1. Enable at least 3 languages
2. Install Entity 404
3. Create a node
4. Translate the node
5. Create a second translation -> the button will be gone

Proposed resolution

Remove the if and use the same access check as for new nodes.