[4.18] tests, net, hot plug: quarantine multiple interfaces hot plug scenario (#5084)

##### What this PR does / why we need it:
Quarantining the scenario that creates 3 additional hot-plug interfaces
will stabilize the module until a proper fix is applied in a future PR.
Backport of
#3455 to
cnv-4.18.

##### Which issue(s) this PR fixes:
Hot-plug tests are showing flakiness because the test tries to hot-plug
too many interfaces (more than 4, which is the maximum allowed for the
VM spec used in this module). Quarantining the scenario that creates 3
additional hot-plug interfaces will stabilize the module until a proper
fix is applied.

##### Special notes for reviewer:

##### jira-ticket:
[CNV-76670](https://issues.redhat.com/browse/CNV-76670)

Signed-off-by: Anat Wax <awax@redhat.com>

Author: Anatw

tests/network/l2_bridge/test_bridge_nic_hot_plug.py

@@ -20,7 +20,7 @@
     set_secondary_static_ip_address,
     wait_for_interface_hot_plug_completion,
 )
-from utilities.constants import FLAT_OVERLAY_STR, SRIOV
+from utilities.constants import FLAT_OVERLAY_STR, QUARANTINED, SRIOV
 from utilities.network import (
     IfaceNotFound,
     assert_ping_successful,
@@ -491,6 +491,10 @@ def test_vmi_spec_updated_with_hot_plugged_interface(
         name="test_multiple_interfaces_hot_plugged",
         depends=["test_vmi_spec_updated_with_hot_plugged_interface"],
     )
+    @pytest.mark.xfail(
+        reason=(f"{QUARANTINED}: Failing due to hot plugging too many interfaces to the VM. Tracked in CNV-76670"),
+        run=False,
+    )
     def test_multiple_interfaces_hot_plugged(
         self,
         running_vm_for_nic_hot_plug,