BE: Wizard: Fix nullable cluster perms check

[Haarolean]

• Breaking change? (if so, please describe the impact and migration path for existing application instances)

What changes did you make? (Give an overview)
Fixes #677

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How Has This Been Tested? (put an "x" (case-sensitive!) next to an item)

• No need to
• Manually (please, describe, if necessary)
• Unit checks
• Integration checks
• Covered by existing automation

Checklist (put an "x" (case-sensitive!) next to all the items, otherwise the build will fail)

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. ENVIRONMENT VARIABLES)
• My changes generate no new warnings (e.g. Sonar is happy)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

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[ivanbishop]

Unable to validate still. A cluster configures OK at container bring up time and I can modify it. Add topics etc but i CANNOT add a new cluster. Still get 500 errors. Attaching error, compose and RBAC config files
rbacconfig.txt
dockercompose.txt
err-nov26.txt

[HirossxD]

DEBUG [parallel-5] i.k.u.s.ClustersStatisticsScheduler: Start getting metrics for kafkaCluster: my-cluster 2024-12-04 14:08:45,281 DEBUG [parallel-8] i.k.u.s.ClustersStatisticsScheduler: Metrics updated for cluster: my-cluster 2024-12-04 14:08:47,433 ERROR [reactor-http-epoll-1] o.s.b.a.w.r.e.AbstractErrorWebExceptionHandler: [271ec9af-27] 500 Server Error for HTTP GET "/api/config" java.lang.IllegalArgumentException: No enum constant io.kafbat.ui.model.ActionDTO.all 

I have simmiliar issue. after I have enabled RBAC, permissions seems to be working but I cannot click on "configure" cluster button in dashboard, it throws this error in logs...

[Haarolean]

@HirossxD that's a separate issue we're aware of, but could you raise an issue here, please? So we don't lose a track of it