API: Get user orgs results in internal server error

[lafriks]

• Gitea version (or commit ref): 1.13.0+dev-648-g5995326d5
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL): https://try.gitea.io/api/v1/users/lafriks/orgs
  • No
  • Not relevant