test, e2e-upgrade: strip copy-mac-from from downloaded bond example

v0.87.0 handler fails with InvalidArgument when copy-mac-from is used
while eth1 is being enslaved into bond0 ("Failed to find interface eth1
for copy-mac-from of iface bond0"). The field was not supported by older
handlers.

Strip the field after extracting the previous-release examples tarball
so that the pre-upgrade createUpgradeCasePolicy call succeeds on old
handler versions.

Signed-off-by: copilot <copilot@github.com>

Co-authored-by: mkowalski <2862927+mkowalski@users.noreply.github.com>

Author: Copilot

hack/prepare-e2e-test-upgrade.sh

@@ -20,6 +20,10 @@ mkdir -p test_logs/e2e/upgrade
     mv ./docs/examples/* .
 )
 
+# copy-mac-from was not supported by older handlers; remove it from the
+# bond example so that the pre-upgrade policy can be applied successfully.
+sed -i '/^\s*copy-mac-from:/d' "${test_e2e_updrade_examples_dir}/bond.yaml"
+
 # download manifests for deployment
 (
     cd $test_e2e_updrade_manifests_dir