Change type of "SentryErrorType#project_id" Global ID

What does this MR do?

The project_id we receive from Sentry is a Sentry Project ID, and not a GitLab Project.

We have been returning this as a GitLab project when creating the Global ID when presenting the type via GraphQL.

This MR updates the type to avoid confusion and, to ensure loading from the Global ID doesn't load the incorrect item.

Refs #235857 (closed)

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