Enable Complement CI tests in the 'latest deps' test run. (#13213)

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

scripts-dev/complement.sh

@@ -101,6 +101,7 @@ if [ -z "$skip_docker_build" ]; then
     echo_if_github "::group::Build Docker image: matrixdotorg/synapse"
     docker build -t matrixdotorg/synapse \
       --build-arg TEST_ONLY_SKIP_DEP_HASH_VERIFICATION \
+      --build-arg TEST_ONLY_IGNORE_POETRY_LOCKFILE \
       -f "docker/Dockerfile" .
     echo_if_github "::endgroup::"