net, e2e: Skip SR-IOV hotplug if FG is disabled

PR kubevirt#10185 introduced the SR-IOV migration-based hotplug
with an E2E test that fails [1] in case the `HotplugNICs`
feature gate is disabled.

The CI system of kubevirt/kubevirtci, has an SR-IOV lane
that deploys a cluster and runs the conformance test mechanism
with a focus on SR-IOV tests[2] without enabling the `HotplugNICs`
feature gate.

This causes the pre-submit jobs in kubevirt/kubevirtci to fail[3],
and requires a maintainer override in order to merge PRs.

As an immediate fix, skip the SR-IOV migration based hotplug tests
if the `HotplugNICs` feature gate is disabled.

The kubevirt/kubevirt tests will not be affected by this change.
A more permanent fix will follow.

[1] https://github.com/kubevirt/kubevirt/blob/cb29e9f87d41deae0d9e1efa6b0cde53ecd8c28a/tests/network/hotplug_sriov.go#L52
[2] https://github.com/kubevirt/project-infra/blob/88e8dbd315a7bc908f637ebe3168f1fe7da97839/github/ci/prow-deploy/files/jobs/kubevirt/kubevirtci/kubevirtci-presubmits.yaml#L53
[3] https://prow.ci.kubevirt.io/view/gs/kubevirt-prow/pr-logs/pull/kubevirt_kubevirtci/1070/check-up-kind-1.27-sriov/1691706923780411392

Signed-off-by: Orel Misan <omisan@redhat.com>

tests/network/hotplug_sriov.go

@@ -49,7 +49,9 @@ var _ = SIGDescribe("[Serial] SRIOV nic-hotplug", Serial, decorators.SRIOV, func
 	sriovResourceName := readSRIOVResourceName()
 
 	BeforeEach(func() {
-		Expect(checks.HasFeature(virtconfig.HotplugNetworkIfacesGate)).To(BeTrue())
+		if checks.HasFeature(virtconfig.HotplugNetworkIfacesGate) {
+			Skip("HotplugNICs feature gate is disabled.")
+		}
 	})
 
 	BeforeEach(func() {