fix(initial-data): fix error on fetching initial data when user does not have any workspaces

[neSpecc]

TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at UserModel.<anonymous> (/usr/src/app/src/models/user.js:239:31)
    at Generator.next (<anonymous>)
    at /usr/src/app/src/models/user.js:8:71
    at new Promise (<anonymous>)
    at __awaiter (/usr/src/app/src/models/user.js:4:12)
    at UserModel.getWorkspacesIds (/usr/src/app/src/models/user.js:236:16)
    at Object.<anonymous> (/usr/src/app/src/resolvers/workspace.js:69:90)
    at Generator.next (<anonymous>)
    at fulfilled (/usr/src/app/src/resolvers/workspace.js:28:58)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)

https://garage.hawk.so/project/5f3e9c71fdac60b3bc70b261/event/690e6de184995d00b343a4eb/69346114c1f613dc5bd31388/overview