Migrate monitor store tests from karma to jest

What does this MR do?

Spring cleaning! There is no need to run these tests in browser, so this MR migrates 3 monitor store tests to jest.

• Move store tests to spec/frontend/monitoring/store
• Replate jasmine specific code
• Remove unused mock data exports

Although many lines appear changed, it was mostly just moving them around.

All credit to https://gitlab.com/gitlab-org/frontend/playground/migrate-karma-to-jest

Screenshots

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

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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team