Re-factor: Move auth related `before_actions` into parent controller

What does this MR do?

This MR re-factors analytics controllers: ApplicationController and ProductivityAnalyticsController to DRY up the auth and license check before_actions. These will be re-used by CodeAnalyticsController coming up in https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14719

The related tests are in ee/spec/controllers/analytics/productivity_analytics_controller_spec.rb, which I prefer to keep there instead of the ApplicationController, because, they belong better with where the related actions are. I am conflicted about re-doing the tests for the ApplicationController too, because the tests will be repeated - we shouldn't get rid of the ProductivityAnalyticsController tests because they test the before_action calls.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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