[DGS-19987] Support new CachedSchemaRegistryClient in SchemaRegistryClientFactory- Port to 7.8.0

[karthikeyanas]

What

Port #3636 to 7.8.0 to unblock flink

Checklist

• Contains customer facing changes? Including API/behavior changes
• Is this change gated behind feature flag(s)? This is just a mocks changes
  • List the LD flags needed to be set to enable this change
• Did you add sufficient unit test and/or integration test coverage for this PR? This is just a Mocks change
  • If not, please explain why it is not required
• Does this change require modifying existing system tests or adding new system tests?
  • If so, include tracking information for the system test changes

References

JIRA: https://confluentinc.atlassian.net/browse/DGS-19987

Test & Review

Changes to mock. No new unit test

[confluent-cla-assistant]

🎉 All Contributor License Agreements have been signed. Ready to merge.
_{Please push an empty commit if you would like to re-run the checks to verify CLA status for all contributors.}

[rayokota]

LGTM