Unarchive an experiment

{  "id": "exp_c6v8b3n5q0w2e7h7d2k9m4x1",  "projectId": "proj_tz4a98xxat96iws9zmbrgj3a",  "name": "Onboarding paywall pricing",  "description": "The monthly-first paywall against the annual-first one after onboarding.",  "hypothesis": "Leading with the annual plan brings more new subscriptions.",  "status": "concluded",  "primaryMetricEventName": "$subscription.created",  "secondaryMetricEventNames": [],  "paywallLocationIds": [    "pw_loc_m4x1c6v8b3n5q0w2e7h7d2k9"  ],  "winningVariantId": "exp_var_n5q0w2e7h7d2k9m4x1c6v8b3",  "featureFlagId": "ff_k9m4x1c6v8b3n5q0w2e7h7d2",  "isArchived": false,  "startedAt": "2026-03-02T09:00:00.000Z",  "endedAt": "2026-04-01T09:00:00.000Z",  "createdAt": "2026-02-27T15:20:00.000Z",  "updatedAt": "2026-04-21T08:00:00.000Z"}

{  "error": {    "type": "invalid_request",    "code": "string",    "message": "string",    "param": "string"  }}

{  "error": {    "type": "unauthenticated",    "code": "invalid_api_key",    "message": "This secret key is not valid."  }}

{  "error": {    "type": "permission_denied",    "code": "permission_denied",    "message": "Insufficient permissions."  }}

{  "error": {    "type": "not_found",    "code": "project_not_found",    "message": "There is no project proj_tz4a98xxat96iws9zmbrgj3a, or this credential cannot use it.",    "param": "projectId"  }}

{  "error": {    "type": "internal",    "code": "internal_error",    "message": "Something went wrong on our side. Try again, and contact support with the Request-Id header if it keeps failing."  }}