Revert "Enable Query Cache for Load balancing"

What does this MR do?

The !46765 (merged) may be related to the master branch spec being broken currently.

Currently on master, runnning bundle exec rspec ee/spec/lib/gitlab/database/load_balancing/load_balancer_spec.rb ee/spec/workers/elastic_namespace_rollout_worker_spec.rb would fail. After reverting the MR it seems to work.

The exact reason has not been found yet. And disabling/enabling the feature flag doesn't seem to affect the result. In order to not block other MRs, I want to suggest reverting this for now.

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
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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

Related to #290733 (closed)