Fix broken ITs after merger of #9485

[tdonohue]

References

• Related to #9485

Description

Fixes several broken tests in RelationshipDeleteRestRepositoryIT after the merger of #9485. Because that PR changed the metadata field for isPersonOfProject relationship from dc.contributor.author to project.investigator, several ITs broke. This fixes those ITs.

The correct metadata field for this relationship is project.investigator as specified in our submission-forms.xml: https://github.com/DSpace/DSpace/blob/main/dspace/config/submission-forms.xml#L517-L531

Instructions for Reviewers

• If ITs all pass this will be merged immediately. Currently ITs are broken on main

[dspace-bot]

Successfully created backport PR for dspace-7_x:

• 9578