Fix calculation of given approvals

What does this MR do?

Fix calculation of given approvals shown in merge request overview. This was reported in an issue comment: #30488 (comment 242631069)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content