jsonrpc: python client: message state constants missing

[Simon-Laux]

  DC_STATE_IN_FRESH = 10,
  DC_STATE_IN_NOTICED = 13,
  DC_STATE_IN_SEEN = 16,
  DC_STATE_OUT_DELIVERED = 26,
  DC_STATE_OUT_DRAFT = 19,
  DC_STATE_OUT_FAILED = 24,
  DC_STATE_OUT_MDN_RCVD = 28,
  DC_STATE_OUT_PENDING = 20,
  DC_STATE_OUT_PREPARING = 18,
  DC_STATE_UNDEFINED = 0,

possibly more are missing, look into constants generated for the typescript jsonrpc bindings for reference, it already excludes some that are not used by the jsonrpc api anymore.

solution: include missing constants in const.py