fix: fix ReviewerID() and let it accept int64

mentioned in commit 37125a1c

mentioned in merge request gitlab-org/cli!2600 (merged)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2789

mentioned in merge request gitlab-com/gl-infra/woodhouse!738

mentioned in merge request gitlab-org/release-tools!4633

mentioned in merge request hojerdev/git-sync!72

mentioned in merge request gitlab-com/gl-infra/oncall-robot-assistant!110

mentioned in merge request fforster/epic-update!44

mentioned in merge request fforster/gitlab-mcp!211

mentioned in merge request gitlab-com/gl-infra/autolabels!137

mentioned in merge request gitlab-com/gl-infra/ringctl!405

mentioned in merge request gitlab-com/gl-infra/platform/runway/runwayctl!1412

mentioned in merge request sickit/token-operator!35