refactor: use "import type" syntax

For some reason, "import { type A }" does not work in some cases:

> node_modules/engine.io-client/build/esm/socket.d.ts:2:15 - error TS1005: ',' expected.

> 2 import { type Packet, type BinaryType, RawData } from "engine.io-parser";

References: https://www.typescriptlang.org/docs/handbook/modules.html#importing-types