d7_pathauto_patterns migration fails with "must define the source_module property" on Drupal 11

Problem/Motivation

When running any migrate command (e.g. drush migrate:status) on a Drupal 11 site that has migrate_drupal enabled, the following error is thrown even if the
d7_pathauto_patterns migration is not being used:

In MigrationPluginManager.php line 118:
  The pathauto_pattern plugin must define the source_module property. 

Steps to reproduce

1. Drupal 11 site with pathauto and migrate_drupal enabled
2. Run drush migrate:status
3. Error is thrown

Root cause

In Drupal 11, PHP 8 attributes take precedence over docblock annotations for plugin discovery. The PathautoPattern source plugin
(src/Plugin/migrate/source/PathautoPattern.php) was partially migrated to use the #[MigrateSource] attribute, but source_module was not carried over:

  // Old annotation (ignored in Drupal 11):
  // @MigrateSource(id = "pathauto_pattern", source_module = "pathauto")                                                                                                        
                                                                                                                                                                                
  // New attribute (missing source_module):                                                                                                                                     
  #[MigrateSource(id: 'pathauto_pattern')]                                                                                                                                      

Drupal\migrate_drupal\MigrationPluginManager::processDefinition() checks for source_module either in the source plugin definition or in the migration's source section. Since
the PHP 8 attribute doesn't include it and the MigrateSource attribute class itself has no source_module parameter, the check fails.

Proposed resolution

Add source_module: pathauto to the source section of migrations/d7_pathauto_patterns.yml:

  source:                                                                                                                                                                       
    plugin: pathauto_pattern
    source_module: pathauto                                                                                                                                                     

Remaining tasks

User interface changes

API changes

Data model changes