Remove RansomLook API key requirement

[adulau]

Motivation

• RansomLook queries do not require authentication, so the module should not force an API key or send an Authorization header.

Description

• Remove api-key from moduleconfig by setting moduleconfig = [] in misp_modules/modules/expansion/ransomlook.py and update moduleinfo["requirements"] to "No API key required.".
• Remove the runtime config check that returned an error when api-key was missing.
• Stop sending the Authorization header; requests now only include User-Agent: misp-modules when calling https://www.ransomlook.io/api/search.
• Update tests/test_ransomlook.py to use an empty config and to assert the unauthenticated request behavior, removing the previous test that enforced an API key.

Testing

• Ran pytest -q tests/test_ransomlook.py, and the suite passed: 2 passed.
• Performed a quick git diff --check to ensure no whitespace errors (no issues reported).

---

Codex Task