build: remove unused lodash.debounce dependency

[HeversonSilva-gif]

Description of change

lodash.debounce is declared in dependencies and @types/lodash.debounce in
devDependencies, but neither is imported anywhere in the project. Debouncing here is
done by BytesWriteDebounce in
src/download/download-engine/streams/download-engine-write-stream/utils/BytesWriteDebounce.ts,
which is written from scratch on top of abortableSleep and does not use lodash.

Every install of ipull therefore resolves and downloads a package it never loads.

Verified at 6954781:

• git grep -E "(from|require\(|import\()\s*['\"]lodash\.debounce" returns nothing, and
  searching the whole of src/ and test/ for any string starting with lodash also
  returns nothing. The only matches in the repository are the two manifest entries and
  their package-lock.json records.
• npm run build (tsc --build) before the change: exit 0. After: exit 0. This is the
  check that matters most here, since a missing module referenced anywhere in the sources
  would fail the build once the package is uninstalled.
• npm run lint before: 4 problems, 0 errors, 4 warnings, exit 0. After: identical.
• npm install reports removed 3 packages — lodash.debounce,
  @types/lodash.debounce, and @types/lodash, which came in only as a dependency of the
  latter.

Node 20.20.0, npm 10.8.2, on Windows.

What I could not verify: npm run test. The suite downloads from
https://quick-lint-js.com and expects a server on localhost:3000, and it did not
finish in my environment. I did not want to tick that box without a run behind it. The
build and lint runs above are on both sides, and no test file references lodash either.

Pull-Request Checklist

• Code is up-to-date with the main branch
• npm run format to apply eslint formatting — N/A, no source file changed
• npm run test passes with this change — not run, see the note above
• This pull request links relevant issues as Fixes #0000 — N/A, no open issue
• There are new or updated unit tests validating the change — N/A, no behaviour change
• Documentation has been updated to reflect this change — N/A, no API change
• The new commits follow conventions explained in
  CONTRIBUTING.md