test(disks): extract DataExport to util.go and add phase watcher

[hardcoretime]

Description

Adds EventPhaseWatcher utility for tracking phase transitions in e2e tests and refactors DataExport functionality.

Changes:

• test/e2e/internal/util/event_watcher.go: Implements EventPhaseWatcher that uses Kubernetes Watch API to track phase changes in real-time instead of polling. Includes helper methods like HasSequence, ContainsPhase, and VerifyPhaseTransitions for verifying phase transitions.

• test/e2e/blockdevice/util.go: Extracts common export utilities (DataExport, IsNFS, needPublishOption) from data_exports.go for reuse.

• test/e2e/blockdevice/vd_phase_transitions.go: Adds VirtualDiskPhaseTransitions test that verifies the expected phase sequence (Ready → Exporting → Ready) during VirtualDisk export using the new EventPhaseWatcher.

• test/e2e/blockdevice/data_exports.go: Removes duplicate export functions, now uses DataExport from util.go.

Why do we need it, and what problem does it solve?

The main goal is to track resource phases during various operations (export, upload, resize, etc.) to detect problems in phase transitions.

EventPhaseWatcher provides a more reliable mechanism by using Kubernetes Watch API to observe phase changes in real-time. This allows tests to verify that resources go through the expected phase sequence and fail early if incorrect phases are observed (e.g., PVCLost, Failed, etc.).

What is the expected result?

Phase sequence verification (Ready → Exporting → Ready) is performed automatically.

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: test
type: chore
summary: "Add EventPhaseWatcher for tracking phase transitions in e2e tests."
impact_level: low