Remove time-profile keys from `default_params.json`

[matt-dray]

Time profile mappings are being retired (https://github.com/The-Strategy-Unit/nhp_planning/issues/606), so we no longer need these elements in the default params.

[matt-dray]

This:

 "time_profile_mappings": {
    "baseline_adjustment": "none",
    "activity_avoidance": {
      "ip": {},
      "op": {},
      "aae": {}
    },
    "efficiencies": {
      "ip": {},
      "op": {}
    },
    "expat": "linear",
    "repat_local": "linear",
    "repat_nonlocal": "linear",
    "non-demographic_adjustment": "none",
    "waiting_list_adjustment": "linear"
  },