Remove obsolete try/catch block for batch ID

Problem/Motivation

#3337513: Fix batch process race conditions by making ‘bid (batch id)’ auto-increment added the code comment,

    try {
      $batch['id'] = $batch['progressive'] ? \Drupal::service(BatchStorageInterface::class)->getId() : 'non-progressive';
    }
    catch (IntegrityConstraintViolationException) {
      // @todo this is here to support the update path to deprecate
      // Connection::nextId(). Remove in Drupal 11.
      // ...
    }

but Drupal 11 is here and that try/catch block has not been removed.

Proposed resolution

Remove the try/catch block.

Remaining tasks

User interface changes

None

Introduced terminology

None

API changes

None

Data model changes

None

Release notes snippet

N/A