feat(testing): allow to specify client options when creating test client

mentioned in commit 34e6e9c0

mentioned in merge request gitlab-org/release-tools!4296 (merged)

mentioned in merge request gitlab-org/cli!2206 (merged)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2567 (merged)

mentioned in merge request gitlab-com/gl-infra/woodhouse!659 (merged)

mentioned in merge request fforster/gitlab-mcp!105 (merged)

mentioned in merge request gitlab-com/gl-infra/autolabels!67 (merged)

mentioned in merge request gitlab-com/gl-infra/ringctl!321 (merged)

mentioned in merge request gitlab-com/gl-infra/platform/runway/runwayctl!1053 (merged)

mentioned in merge request gitlab-org/container-registry!2376 (merged)

mentioned in merge request schober-server/kubernetes/images/gitlab-token-refresher!18 (merged)

mentioned in merge request fforster/epic-update!12 (merged)

mentioned in merge request sue445/tanuki_reminder!254 (merged)

mentioned in merge request sue445/create-merge-request!138 (merged)