Before reporting an issue

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Area

core

Describe the bug

When the admin-cli clients has been deleted in one realm, the upate from KC <26 to KC 26.x fails with the following error:

```json
{"timestamp":"2024-12-11T07:29:23.579094554Z","sequence":9861,"loggerClassName":"org.jboss.logging.Logger","loggerName":"org.keycloak.quarkus.runtime.cli.ExecutionExceptionHandler","level":"ERROR","message":"ERROR: Cannot invoke \"org.keycloak.models.ClientModel.setFullScopeAllowed(boolean)\" because \"adminCliClient\" is null","threadName":"main","threadId":1,"mdc":{},"ndc":"","hostName":"xxxx","processName":"/usr/lib/jvm/java-21-openjdk-21.0.5.0.11-2.el9.x86_64/bin/java","processId":1}
```

Version

26.0.7

Regression

[X] The issue is a regression

Expected behavior

The update works even if the client does not exists.

Actual behavior

KC startup fails with error message.

How to Reproduce?

Run Keycloak in version <26. Delete the admin-cli client in one realm. Update to KC 26.x.

Anything else?

No response