OpenWA: VIEWER API keys can read WhatsApp group invite codes

OpenWA is a free, open source, self-hosted WhatsApp API gateway. Prior to 0.23.5, the GET /api/sessions/{sessionId}/groups/{groupId}/invite-code endpoint and the GroupGetInviteCode MCP tool have no OPERATOR role requirement, allowing a valid VIEWER key scoped to a session to retrieve an active group invite code. The invite code is a transferable WhatsApp bearer capability, so an external account can join a group administered by the session without an OpenWA credential, gain read and post access to the group, and retain membership after the VIEWER key is revoked. Affected deployments are those that issue VIEWER keys to parties who should not be able to add accounts to administered groups; OPERATOR and ADMIN access is intended. This issue is fixed in version 0.23.5.