test(dataflowaffinity): migrate to Ginkgo/Gomega

[hxrshxz]

Ⅰ. Describe what this PR does

Migrates unit tests in pkg/controllers/v1alpha1/fluidapp/dataflowaffinity/ from the standard testing package to Ginkgo v2/Gomega, adds a package-level suite bootstrap (suite_test.go), and expands test coverage from 39% to 81.4% by adding specs for Reconcile, ControllerName, ManagedResource, and NewDataOpJobReconciler.

Ⅱ. Does this pull request fix one issue?

#5676

Ⅲ. List the added test cases (unit test/integration test) if any, please explain if no tests are needed.

• ControllerName — asserts the constant string is returned
• ManagedResource — asserts a *batchv1.Job is returned
• NewDataOpJobReconciler — asserts the constructor wires client correctly
• Reconcile (4 cases): job not found (propagates error), job with cronjob label (skipped/no-requeue), valid fluid job without affinity annotation (annotation injected), complete job with succeeded pod (node labels injected)
• injectPodNodeLabelsToJob (2 cases): succeeded pod injects annotations; failed-only pod returns error

Ⅳ. Describe how to verify it

go test ./pkg/controllers/v1alpha1/fluidapp/dataflowaffinity/... -v -count=1
go test ./pkg/controllers/v1alpha1/fluidapp/dataflowaffinity/... -coverprofile=/tmp/c.out -covermode=atomic && go tool cover -func=/tmp/c.out | grep total

Ⅴ. Special notes for reviews

N/A