fix: remove duplicate bearer() method

[susheela-hinchig]

What

lib/test.js defines bearer(token) twice. The two definitions are identical,
so the second just shadows the first. This removes the duplicate (and its
duplicate comment block), leaving a single definition.

Why it wasn't caught

The lint config extends airbnb-base/legacy, which is the ES5 ruleset and
doesn't include no-dupe-class-members, so npm run lint passes despite the
duplicate. Running ESLint with that rule enabled flags it:

lib/test.js
  227:3  error  Duplicate name 'bearer'  no-dupe-class-members

Verification

• npm run lint passes
• npm test passes (130 passing) — .bearer() is already covered in
  test/supertest.js, and behaviour is unchanged since the removed copy was
  identical

No functional change; this just deletes dead duplicate code.

Checklist

• I have ensured my pull request is not behind the main or master branch of the original repository.
• I have rebased all commits where necessary so that reviewing this pull request can be done without having to merge it first.
• I have written a commit message that passes commitlint linting.
• I have ensured that my code changes pass linting tests.
• I have ensured that my code changes pass unit tests.
• I have described my pull request and the reasons for code changes along with context if necessary.