simplify logic in ConfigManager::getEntityTypeIdByName()

Problem/Motivation

The logic in ConfigManager::getEntityTypeIdByName() is needlessly complicated:

  public function getEntityTypeIdByName($name) {
    $entities = array_filter($this->entityTypeManager->getDefinitions(), function (EntityTypeInterface $entity_type) use ($name) {
      return ($entity_type instanceof ConfigEntityTypeInterface && $config_prefix = $entity_type->getConfigPrefix()) && strpos($name, $config_prefix . '.') === 0;
    });
    return key($entities);
  }

It's using array_filter with a custom filter callback to find those entity types whose config prefix matches the given config $name.
But it then returns only the first one found, using key() -- since there should only be one.

I think it would be much easier to read and debug if it did this:

foreach (($this->entityTypeManager->getDefinitions() as $entity_type) {
 if (condition ... ) {
  return entity type ID
 }
}

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet