fix: Gettext.Extractor references no function clause matching

[feng19]

  1) test merge_template/2 allowed messages are kept (Gettext.ExtractorTest)
     test/gettext/extractor_test.exs:90
     ** (FunctionClauseError) no function clause matching in anonymous fn/1 in Gettext.Extractor.protected?/2

     The following arguments were given to anonymous fn/1 in Gettext.Extractor.protected?/2:
     
         # 1
         [{"foo.ex", 1}, {"bar.ex", 1}]
     
     code: assert Extractor.merge_template(old, new, excluded_refs_from_purging: ~r{^web/static/}) ==
     stacktrace:
       (gettext 0.23.0-dev) lib/gettext/extractor.ex:425: anonymous fn/1 in Gettext.Extractor.protected?/2
       (elixir 1.14.1) lib/enum.ex:4136: Enum.any_list/2
       (gettext 0.23.0-dev) lib/gettext/extractor.ex:295: anonymous fn/3 in Gettext.Extractor.merge_template/3
       (elixir 1.14.1) lib/enum.ex:4249: Enum.flat_map_list/2
       (gettext 0.23.0-dev) lib/gettext/extractor.ex:292: Gettext.Extractor.merge_template/3
       test/gettext/extractor_test.exs:107: (test)

[coveralls]

Pull Request Test Coverage Report for Build a6664f8c0297d107b5b1e585d9d7a1cc088a95ec-PR-357

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.738%

---

Totals
Change from base Build 3d168822d276e0e8c87cf8b724a374630709a9a0:	0.0%
Covered Lines:	529
Relevant Lines:	583

---

💛 - Coveralls