[MM-57517] Add exact user ID lookup to the search query for Users (#26661)

* [MM-57517] Add exact user ID lookup to the search query for Users

* Fix lint

* Add test for ID search

server/channels/store/sqlstore/user_store.go

@@ -1613,6 +1613,8 @@ func generateSearchQuery(query sq.SelectBuilder, terms []string, fields []string
 			}
 			termArgs = append(termArgs, fmt.Sprintf("%%%s%%", strings.TrimLeft(term, "@")))
 		}
+		searchFields = append(searchFields, "Id = ?")
+		termArgs = append(termArgs, strings.TrimLeft(term, "@"))
 		query = query.Where(fmt.Sprintf("(%s)", strings.Join(searchFields, " OR ")), termArgs...)
 	}