Add AgentID OAuth provider support

Minor Changes

• Add agentid to OAuthProvider and OAUTH_PROVIDERS to support the "Continue with AgentID" OAuth flow. Instances with the connection enabled now render a "Continue with AgentID" button, with the AgentID mark tinted to match the theme's foreground color so it stays legible in dark mode. (#9735) by @wyattjoh

Patch Changes

• The organization Security page now lists every enterprise SSO connection of the organization, each with its own status, domains, and actions. The SSO wizard edits one explicit connection, and a banner names it when the organization has more than one. Changing a provider or removing a connection now targets that connection instead of the first one returned by the API. (#9729) by @NicolasLopes7