test(client): use get instead of head requests

Apparently, webpack-dev-server does not handle HEAD requests,
see "Note for webpack-dev-server users" at:
https://github.com/bahmutov/start-server-and-test/blob/master/README.md
For some reason this hasn't been a problem until now when a dependency
update bumped webpack-dev-middleware from 7.2.1 to 7.3.0,
the regression described in this issue might be real:
webpack/webpack-dev-middleware#1920

client/package.json

@@ -22,7 +22,7 @@
     "test": "jest --reporters=@trshcmpctr/jest-stdout-reporter --silent",
     "test:debug": "NODE_OPTIONS=--inspect jest --runInBand --no-cache",
     "test:watch": "jest --watch",
-    "test:cypress": "start-server-and-test serve http://localhost:8080 cy:run",
+    "test:cypress": "start-server-and-test serve http-get://localhost:8080 cy:run",
     "type-check": "tsc",
     "watch": "webpack --config webpack.config.cjs --watch"
   },