handle the missing mlmd service-ca cert gracefully

[HumairAK]

This will handle the following dspo log message more gracefully:

2024-10-18T16:25:29-04:00       INFO    Applying ML-Metadata (MLMD) Resources   {"namespace": "dspa2", "dspa_name": "sample"}
2024-10-18T16:25:29-04:00       INFO    Updating components endpoints   {"namespace": "dspa2", "dspa_name": "sample"}
2024-10-18T16:25:29-04:00       ERROR   Reconciler error        {"controller": "datasciencepipelinesapplication", "controllerGroup": "datasciencepipelinesapplications.opendatahub.io", "controllerKind": "DataSciencePipelinesApplication", "DataSciencePipelinesApplication": {"name":"sample","namespace":"dspa2"}, "namespace": "dspa2", "name": "sample", "reconcileID": "0a19a4b2-fd85-4094-8be8-c7a57eddd4c3", "error": "secret containing the certificate for MLMD gRPC Server was not created yet"}
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler
        /home/hukhan/go/1.21.3/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:324
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem
        /home/hukhan/go/1.21.3/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:265
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2
        /home/hukhan/go/1.21.3/pkg/mod/sigs.k8s.io/controller-runtime@v0.15.0/pkg/internal/controller/controller.go:226

This is an expected state, and should not print a stack trace, but we still want to stacktrace other errors. So I've introduced a custom error for this scenario. In the future we should handle this via states for components, for example "state: loading" or "state: waitingOnDependency", instead of errors, but this should be approached consistently for all components, this pr is a simple fix until then.

Result:

2024-10-18T16:29:32-04:00       INFO    Applying ML-Metadata (MLMD) Resources   {"namespace": "dspa2", "dspa_name": "sample"}
2024-10-18T16:29:32-04:00       INFO    MLMD gRPC Server cert secret not found, this is likely because it has not been created yet      {"namespace": "dspa2", "dspa_name": "sample"}
2024-10-18T16:29:32-04:00       INFO    Updating components endpoints   {"namespace": "dspa2", "dspa_name": "sample"}

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Once this PR has been reviewed and has the lgtm label, please ask for approval from humairak. For more information see the Kubernetes Code Review Process.

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[dsp-developers]

Change to PR detected. A new PR build was completed. A new image has been built to help with testing out this PR: quay.io/opendatahub/data-science-pipelines-operator:pr-728

[dsp-developers]

Change to PR detected. A new PR build was completed. A new image has been built to help with testing out this PR: quay.io/opendatahub/data-science-pipelines-operator:pr-728

[VaniHaripriya]

/lgtm

[openshift-merge-robot]

PR needs rebase.

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[diegolovison]

Is it possible to have a test for this?