Extract api urls from Sentry Client

What does this MR do?

I extracted methods for getting the sentry api urls out of the client so that they are not private to the client and can be used in the feature specs that I am working on.

Decided to break out just this portion of the change for easier review. :)

This is a refactor with no changes to functionality.

Part of #36695 (closed)

Conformity

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

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers