[lib] Remove dangling reduceUserInfos function from update specs

Summary: After some refactoring of `user-reducer.js` some time ago, this function is no longer used, and can be removed.

Test Plan: Flow, consulting Tomek

Reviewers: tomek

Reviewed By: tomek

Differential Revision: https://phab.comm.dev/D13502

lib/shared/updates/delete-account-spec.js

@@ -10,7 +10,6 @@ import type {
   AccountDeletionUpdateData,
   AccountDeletionUpdateInfo,
 } from '../../types/update-types.js';
-import type { UserInfos } from '../../types/user-types.js';
 import { tNumber, tShape, tUserID } from '../../utils/validation-utils.js';
 
 export const deleteAccountSpec: UpdateSpec<
@@ -60,14 +59,6 @@ export const deleteAccountSpec: UpdateSpec<
     }
     return operations;
   },
-  reduceUserInfos(state: UserInfos, update: AccountDeletionUpdateInfo) {
-    const { deletedUserID } = update;
-    if (!state[deletedUserID]) {
-      return state;
-    }
-    const { [deletedUserID]: deleted, ...rest } = state;
-    return rest;
-  },
   rawUpdateInfoFromRow(row: Object) {
     const content = JSON.parse(row.content);
     return {

lib/shared/updates/update-spec.js

@@ -71,7 +71,6 @@ export type UpdateSpec<
     state: ?CurrentUserInfo,
     update: UpdateInfo,
   ) => ?CurrentUserInfo,
-  +reduceUserInfos?: (state: UserInfos, update: UpdateInfo) => UserInfos,
   +reduceCalendarThreadFilters?: (
     filteredThreadIDs: $ReadOnlySet<string>,
     update: UpdateInfo,