Rename subject to wrapper

What does this MR do?

This refactors the on-demand scans form specs to align some objects' naming with the rest of the codebase. We experimented with naming things around the term subject, but it never propagated to other specs making them look like inconsistencies when compared to the rest of the codebase.

• Renames subject to wrapper.
• Renames subjectMounterFactory to createComponentFactory.
• Renames mountSubject to createComponent.
• Renames mountShallowSubject to createShallowComponent.

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • [-] I have included a changelog entry.
  • I have not included a changelog entry because those are backstage changes.

Related to #326200 (closed)