Moodle 4.1 testing -> Some issues found

[marxjohnson]

Tested on Ubuntu 22.04/PHP 8 with PostgreSQL 14 and MySQL 8.

I found the following issues:

• Use of deprecated get_all_user_name_fields function
• Obsolete "social" profile fields (icq, aim)

And some issues not directly related to 4.1:

• If no users are selected by the users cleaner, the queries fail due to passing an empty string to the IN SQL conditions.
• If all unit tests for the plugin and sub-plugins are run as a single suite, some tests fail due to the dryrun option being set in a static variable and not reset..

I also found an unrelated issue which appears to be PostgreSQL-specific, that I will log separately.