Bug 32224: Add cypress to yarn commands

Either I am missing something obvious, or we need to add cypress to the scripts of package.json

With /kohadevbox/node_modules only (ie. without $SYNC_REPO/node_modules), I cannot run
  yarn run cypress run

`cypress run` is working with an adjusted PATH (see https://gitlab.com/koha-community/koha-testing-docker/-/issues/313#note_1173792905) but I think both should work.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

package.json

@@ -45,7 +45,8 @@
     "build_js": "webpack --mode production",
     "watch_js": "webpack --mode development --watch",
     "css": "gulp css",
-    "watch": "gulp watch"
+    "watch": "gulp watch",
+    "cypress": "cypress"
   },
   "repository": {
     "type": "git",