fix: modify cleanup path to always delete link

[QxBytes]

Reason for Change:

Previously, DeleteEndpointsImpl would return an error if it failed to remove routes, skipping any further clean up logic. This could lead to the vnet veth device not being deleted (The vnet veth device is one end of the container's veth pair, the other resides in either the container if it was successfully moved, or still in the vnet ns if it was not moved). On subsequent adds, an error would pop up mentioning the pair already exists.

Issue Fixed:

The PR ensures both pieces of logic always run, even if there is an error (which is logged). Unit tests have been added to verify the correct code paths are hit and there don't seem to be other methods in the delete flow that have this problem for this scenario.

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• relevant PR labels added

Notes:
Tested on a multitenancy transparent vlan linux setup.

[Copilot]

Pull Request Overview

This PR modifies the cleanup path in Azure Container Networking's transparent VLAN endpoint handling so that both route deletion and veth deletion are attempted, even if deleting routes fails. Key changes include:

• Removing error propagation from DeleteEndpointsImpl so that errors are now only logged.
• Updating related unit tests to reflect the new behavior.
• Enhancing the mock netlink package to allow injection of custom DeleteLink behavior.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
network/transparent_vlan_endpointclient_linux_test.go	Removed error expectations from tests and added a test verifying cleanup on failure
network/transparent_vlan_endpointclient_linux.go	Modified DeleteEndpoints and DeleteEndpointsImpl to log errors without returning them
netlink/mocknetlink.go	Added DeleteLinkFn support to allow mock customization

Comments suppressed due to low confidence (2)

network/transparent_vlan_endpointclient_linux.go:650

• Since DeleteEndpointsImpl no longer returns an error, ensure that all callers are updated to handle this change appropriately and consider updating the function’s comments to clarify that errors are now only logged.

func (client *TransparentVlanEndpointClient) DeleteEndpointsImpl(ep *endpoint, _ func() (int, error)) {

network/transparent_vlan_endpointclient_linux_test.go:733

• [nitpick] It may be beneficial to add assertions that verify the correct error log messages are emitted when route deletion fails to further improve test coverage for the error paths.

require.Equal(t, 1, errOnDeleteRouteFlag, "error must occur during delete route path")

[QxBytes]

/azp run Azure Container Networking PR

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/azp run Azure Container Networking PR

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/azp run Azure Container Networking PR

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