VMware: wait for NSX DV port group readiness

[Dogface2k]

Description

This PR prevents VMware NSX-backed guest network implementation from failing when vCenter has not yet exposed the backing distributed virtual port group immediately after NSX segment creation.

The NSX branch in HypervisorHostHelper.prepareNetwork now uses the existing bounded waitForDvPortGroupReady path. The change does not retry the CloudStack mutation or create a second network; it only waits for vCenter inventory visibility before returning the already-created port group.

A regression test simulates an empty first vCenter lookup followed by the port group becoming available. The existing immediate-availability behavior remains covered.

Fixes: #13752

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

Not applicable.

How Has This Been Tested?

Targeted regression and baseline tests were run on the 4.22 branch with Java 17:

HypervisorHostHelperTest#testPrepareNetwork
HypervisorHostHelperTest#testPrepareNetworkWaitsForNsxDvPortGroup

Tests run: 2, Failures: 0, Errors: 0, Skipped: 0

The Maven reactor built all 18 required modules successfully, including cloud-vmware-base, with zero Checkstyle violations.

How did you try to break this feature and the system with this change?

The regression test makes the first vCenter DV port group query return no result and the second return the expected port group. The pre-existing immediate-availability test also runs to verify the normal fast path remains unchanged. The production path remains bounded by the existing readiness timeout and returns failure if the port group never appears.

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