Support X_if_ee methods for QA tests

What does this MR do?

For the QA tests to use the new injection methods, we must require the initializer and ensure that the "constantize" method is available.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content