Modify ReactiveCaching concern

What does this MR do?

1. When the ReactiveCaching concern finishes a job, it schedules the job to be executed again after reactive_cache_refresh_interval in order to keep the cache fresh. Add a new boolean attribute to ReactiveCaching called reactive_cache_enqueue_updates. The default value of this attribute is true. Setting it to false prevents re-enqueuing of jobs by reactive caching.

2. Move the exclusive lease key name into a method, so that the method can be overridden in order to override the default exclusive lease key name.

Issue: #32351 (closed)

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