conn-disrupt: Allowlist CT buffer drops

Commit 94ec45a ("bpf: unconditionally migrate cilium_calls_* maps
during ELF load") in main fixed a set of packet drops that can happen
during a short time on agent restarts. Now that our CI is more sensitive
to such drops, we are noticing them on all stable branches.

Unfortunately, the fix is too invasive to confidently backport to v1.12.
Instead, this commit allowlist the CT buffer drops we are seeing in CI.

Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>

.github/workflows/tests-ipsec-upgrade.yaml

@@ -336,6 +336,7 @@ jobs:
         uses: ./.github/actions/conn-disrupt-test
         with:
           job-name: ipsec-upgrade-${{ matrix.name }}
+          extra-connectivity-test-flags: --expected-drop-reasons "+Failed to update or lookup TC buffer"
           operation-cmd: |
             cd /host/