Warning on entity delete

Problem/Motivation

The form_mode_control_entity_delete function is called for all entity deletions (via hook_entity_delete), but it only needs to handle EntityFormDisplayInterface and RoleInterface. When other entities (like custom ones) are deleted, it still iterates the config, which can fail if the config has null values.

Steps to reproduce

Precondition: form_mode_control module enbled.

1. Define a custom entity.
2. Try to remove it.

The result: Warning: foreach() argument must be of type array|object, null given in form_mode_control_entity_delete()

Proposed resolution

Early return if entity is has no EntityFormDisplayInterface and RoleInterface.

if (!($entity instanceof EntityFormDisplayInterface) && !($entity instanceof RoleInterface)) {
    return;
}