Revert "Migration to create ImportantNotice table"

This reverts commit 61bfbb3.

Author: thomasleese

db/migrate/20251017133425_create_important_notices.rb

@@ -387,23 +387,6 @@
     t.index ["immunisation_import_id", "vaccination_record_id"], name: "idx_on_immunisation_import_id_vaccination_record_id_588e859772", unique: true
   end
 
-  create_table "important_notices", force: :cascade do |t|
-    t.datetime "created_at", null: false
-    t.datetime "dismissed_at"
-    t.bigint "dismissed_by_user_id"
-    t.bigint "patient_id", null: false
-    t.datetime "recorded_at", null: false
-    t.bigint "team_id", null: false
-    t.integer "type", null: false
-    t.datetime "updated_at", null: false
-    t.bigint "vaccination_record_id"
-    t.index ["dismissed_by_user_id"], name: "index_important_notices_on_dismissed_by_user_id"
-    t.index ["patient_id", "type", "recorded_at", "team_id"], name: "index_notices_on_patient_and_type_and_recorded_at_and_team", unique: true
-    t.index ["patient_id"], name: "index_important_notices_on_patient_id"
-    t.index ["team_id"], name: "index_important_notices_on_team_id"
-    t.index ["vaccination_record_id"], name: "index_important_notices_on_vaccination_record_id"
-  end
-
   create_table "local_authorities", id: false, force: :cascade do |t|
     t.datetime "created_at", null: false
     t.date "end_date"
@@ -1032,10 +1015,6 @@
   add_foreign_key "immunisation_imports_sessions", "sessions", on_delete: :cascade
   add_foreign_key "immunisation_imports_vaccination_records", "immunisation_imports", on_delete: :cascade
   add_foreign_key "immunisation_imports_vaccination_records", "vaccination_records", on_delete: :cascade
-  add_foreign_key "important_notices", "patients"
-  add_foreign_key "important_notices", "teams"
-  add_foreign_key "important_notices", "users", column: "dismissed_by_user_id"
-  add_foreign_key "important_notices", "vaccination_records"
   add_foreign_key "location_programme_year_groups", "location_year_groups", on_delete: :cascade
   add_foreign_key "location_programme_year_groups", "programmes", on_delete: :cascade
   add_foreign_key "location_year_groups", "locations", on_delete: :cascade