spec: add tests for the autoUpdater on macOS that actually test if it works (#17442)

* spec: add tests for the autoUpdater on macOS that actually test if it works

* spec: add express as dep

* spec: add logic to auto-trust self-signed certificate and not run autoupdate specs on MAS

* build: fix the step name for importing the codesign cert

* chore: update updater spec PR as per feedback

* fix: s/atomBinding/electronBinding

* build: use spawn instead of exec

script/codesign/get-trusted-identity.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+set -e
+
+valid_certs=$(security find-identity -p codesigning -v)
+if [[ $valid_certs == *"1)"* ]]; then
+  first_valid_cert=$(echo $valid_certs | sed 's/ \".*//' | sed 's/.* //')
+  echo $first_valid_cert
+  exit 0
+else
+  # No Certificate
+  exit 0
+fi