fix: tarball bundling - import assertion replacement

[mrstork]

Summary

Fixes FRB-2115

Tested with the following block of code:

import data1 from './data.json' assert { type: 'json' };
export { default } from './data.json' assert { type: 'json' };
import * as data2 from './data.json' assert { type: 'json' };
import assert from './assert.json' with { type: 'json' };
import { foo } from './data.json' assert { type: 'json' };
import data3 from './data.json' with { type: 'json' };
import data4 from './data.json';
import data5 from './data.json' assert { type: 'json' };
import data6 from './data.json' assert { type: 'json' };

import a from './a.json' assert { type: 'json' };
import b from './b.css' assert { type: 'css' };
import c from './c.js';

import d from './a.json' with { type: 'json' };
import e from './b.css' with { type: 'css' };
import f from './c.js';

---

For us to review and ship your PR efficiently, please perform the following steps:

• Open a bug/issue before writing your code 🧑‍💻. This ensures
  we can discuss the changes and get feedback from everyone that should be involved. If you`re fixing a typo or
  something that`s on fire 🔥 (e.g. incident related), you can skip this step.
• Read the contribution guidelines 📖. This ensures
  your code follows our style guide and passes our tests.
• Update or add tests (if any source code was changed or added) 🧪
• Update or add documentation (if features were changed or added) 📝
• Make sure the status checks below are successful ✅

A picture of a cute animal (not mandatory, but encouraged)