fix(emacs): work around "Feature `project' is now provided by a different file"

Running our Emacs plugin tests with Emacs 27 on a fresh clone (i.e. no MELPA
cache) fails:

```
$ ./plugin/emacs/test-emacs.sh
[snip]
   passed   7/10  quicklintjs-flymake-parse-errors-and-warnings (0.000134 sec)
Eager macro-expansion failure: (error "Feature `project' is now provided by a different file /__w/quick-lint-js/quick-lint-js/plugin/emacs/.melpa-cache/project-0.11.1/project.elc")
Eager macro-expansion failure: (error "Feature `project' is now provided by a different file /__w/quick-lint-js/quick-lint-js/plugin/emacs/.melpa-cache/project-0.11.1/project.elc")
Test quicklintjs-is-in-eglot-servers backtrace:
  signal(error ("Feature `project' is now provided by a different f...
  error("Feature `%S' is now provided by a different file %..." projec
  require-with-check(project)
  mapc(require-with-check (project flymake xref jsonrpc external-compl
  (let ((reload (if (fboundp 'require-with-check) #'require-with-check
  (progn (let ((reload (if (fboundp 'require-with-check) #'require-wit
  eval((progn (let ((reload (if (fboundp 'require-with-check) #'requir
  #f(compiled-function (&rest body) "Like `progn', but evaluates the b
  (eval-and-compile (let ((reload (if (fboundp 'require-with-check) #'
  eval-buffer(#<killed buffer> nil "/__w/quick-lint-js/quick-lint-js/p
  load-with-code-conversion("/__w/quick-lint-js/quick-lint-js/plugin/e
  require(eglot)
  eval-buffer(#<killed buffer> nil "/__w/quick-lint-js/quick-lint-js/p
  load-with-code-conversion("/__w/quick-lint-js/quick-lint-js/plugin/e
  require(eglot-quicklintjs)
  (closure (t) nil (let* ((fn-20 #'>=) (args-21 (condition-case err (l
  ert--run-test-internal(#s(ert--test-execution-info :test #s(ert-test
  ert-run-test(#s(ert-test :name quicklintjs-is-in-eglot-servers :docu
  ert-run-or-rerun-test(#s(ert--stats :selector t :tests ... :test-map
  ert-run-tests(t #f(compiled-function (event-type &rest event-args) #
  ert-run-tests-batch(nil)
  ert-run-tests-batch-and-exit()
  quicklintjs-test-main()
  command-line-1(("-L" "." "-l" "test/quicklintjs-test.el" "-f" "quick
  command-line()
  normal-top-level()
Test quicklintjs-is-in-eglot-servers condition:
    (error "Feature `project' is now provided by a different file /__w/quick-lint-js/quick-lint-js/plugin/emacs/.melpa-cache/project-0.11.1/project.elc")
   FAILED   8/10  quicklintjs-is-in-eglot-servers (0.010112 sec)
   passed   9/10  quicklintjs-is-in-flycheck-checkers (0.000109 sec)
   passed  10/10  quicklintjs-is-in-lsp-clients (0.002524 sec)

Ran 10 tests, 9 results as expected, 1 unexpected (2025-06-16 00:18:10+0000, 0.386571 sec)

1 unexpected results:
   FAILED  quicklintjs-is-in-eglot-servers
```

Running tests again doesn't have this issue. (A filled MELPA cache fixes the
problem.)

Work around this issue with a hack to make the tests pass.

Author: strager

plugin/emacs/test/quicklintjs-test.el

@@ -41,6 +41,13 @@
   (quicklintjs-install-deps (if (>= emacs-major-version 26)
                                 '(flycheck eglot lsp-mode)
                               '(flycheck)))
+
+  ; HACK(strager): Work around error:
+  ; Feature `project' is now provided by a different file
+  ; /__w/quick-lint-js/quick-lint-js/plugin/emacs/.melpa-cache/project-0.11.1/project.elc"
+  ; https://github.com/joaotavora/eglot/discussions/1436
+  (delete 'project features)
+
   (def-flycheck-tests)
   (def-eglot-tests)
   (def-lsp-tests)