fix: ovsdb.GetOvsPortForContIface should not return error if iface not found

[ykulazhenkov]

What this PR does / why we need it:
Currently, the function returns "", false, err if the interface is not found.
The function's signature and usage assume that the function should not return an error if the interface is not found.

ovs-cni/pkg/plugin/plugin.go

Line 315 in 7434914

portName, portFound, err := getOvsPortForContIface(ovsDriver, args.IfName, args.Netns)

Fix the function to return "", false, nil if the interface is not found.
This change fixes CmdDel for the scenario when It is called after a failed CmdAdd or when the port is manually removed from the ovs.
Special notes for your reviewer:

Release note:

"NONE"

cc @SchSeba @e0ne

[kubevirt-bot]

Hi @ykulazhenkov. Thanks for your PR.

I'm waiting for a k8snetworkplumbingwg member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[SchSeba]

/ok-to-test

[SchSeba]

/lgtm
/approve

[kubevirt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: SchSeba, ykulazhenkov

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[SchSeba]

/retest