Token type name is not set for custom blocks

Workflow participants provides tokens for existing entity types, however it also specifies "subtypes", which the Token API does not appear to support.

 if ($entity_type->entityClassImplements(EditorialContentEntityBase::class)) {
        $types[$entity_type->id()]['workflow_participants'] = [
          'name' => $this->t('Workflow participants for @type', ['@type' => $entity_type->getLabel()]),
          'description' => $this->t('Tokens for workflow participants.'),
        ];
    ...

These tokens are also added as part of hook_token_info() rather than hook_token_info_alter(), even though they are supplementing the set of tokens provided by the Token module.

These two things combine to form a bug that prevents the block_content token type from receiving its basic information. i.e.

1. When collecting token information, hook_token_info() is invoked and Workflow Participants ends up adding an entry for $info['types']['block_content']['workflow_participants'].
2. The alter hooks are run and token_token_info_alter() gets invoked.
3. It tries to populate a few properties like name for block_content, but sees that the array key already exists, so it assumes that something else already put the correct information there and skips over it, leaving it without a name.