\Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::auditfilesMergeFileReferencesBatchMergeProcessBatch typehints files being kept as an array, but the code is called with an int

Problem/Motivation

\Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::auditfilesMergeFileReferencesBatchMergeProcessBatch type hints $files_being_merged as an array.
Similarly \Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::$fileIds is type-hinted as an array.

However
\Drupal\auditfiles\ServiceAuditFilesMergeFileReferences::auditfilesMergeFileReferencesBatchMergeCreateBatch sets up the batch task using each separate file ID - these are integers and hence this causes a fatal error because an int isn't an array.

Similarly in \Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::dispatch it calls to \Drupal\auditfiles\ServiceAuditFilesMergeFileReferences::auditfilesMergeFileReferencesBatchMergeProcessFile using \Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::$fileIds

Which is the reverse, passing an array instead of an integer

Steps to reproduce

Try to use the merge file reference function

Proposed resolution

Remove the array typehints from \Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::$fileIds and \Drupal\auditfiles\Batch\AuditFilesMergeFileReferencesBatchProcess::auditfilesMergeFileReferencesBatchMergeProcessBatch

Remaining tasks

User interface changes

API changes

Data model changes