test(juicefs): migrate data_migrate_test.go to Ginkgo/Gomega (#5604)

* test(juicefs): migrate data_migrate_test.go to Ginkgo/Gomega

Signed-off-by: Harsh <harshmastic@gmail.com>

* fix: remove os.TempDir usage to resolve SonarCloud security warning

Replaced filepath.Join(os.TempDir(), ...) with direct filename pattern checks.
The test intent is preserved - we still verify the generated filename contains
the expected pattern.

Signed-off-by: Harsh <harshmastic@gmail.com>

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Signed-off-by: Harsh <harshmastic@gmail.com>

Author: hxrshxz