[fix] ensure that test.pyright installs pyright

nodejs.ensure only sets up NVM if there isn't a system-wide
installation of Node that matches our NODE_MINIMUM_VERSION.

The ubuntu image in the CI comes with an up to date node version,
so pyright from .nvm_packages is never installed.

This commit fixes this by introducing a package.json file.

manage

@@ -687,9 +687,10 @@ test.pylint() {
 test.pyright() {
     build_msg TEST "[pyright] static type check of python sources"
     nodejs.ensure
+    npm install
     # We run Pyright in the virtual environment because Pyright
     # executes "python" to determine the Python version.
-    pyenv.cmd pyright -p pyrightconfig-ci.json
+    pyenv.cmd npx --no-install pyright -p pyrightconfig-ci.json
     dump_return $?
 }