fix MySQLSchemaTool FK introspection under ONLY_FULL_GROUP_BY

[cironapo]

Type of Change

• 🐛 Bug fix

Description

What does this PR do?

Includes kcu.ORDINAL_POSITION in the SELECT DISTINCT list of MySQLSchemaTool::getRelationships().

Why is this change needed?

MySQL/MariaDB with ONLY_FULL_GROUP_BY reject DISTINCT + ORDER BY on columns not in the SELECT list (error 3065), so analyze_mysql_database_schema crashes before returning schema.

How does this change should be used and documented?

No API/docs changes. Existing MySQLSchemaTool usage keeps working.

Related Issues

Testing

• I have tested this change locally
• I have added/updated unit tests where appropriate
• All existing tests pass
• I have tested this with different PHP versions (if applicable)

Breaking Changes

• No breaking changes

Documentation

• No documentation changes needed

Checklist

• My code follows the project's coding standards (PHPStan)
• I have performed a self-review of my code
• My changes generate no new warnings or errors
• My commit messages are clear and descriptive
• This PR addresses only ONE specific goal/issue