Rename isLoading to isLoadingVulnerability

• Related issue: #205311 (closed)

What does this MR do?

This improves a property's naming by making it more specific to better reflect what it does.

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