Added playwright install step to signature-extension example to avoid failure after PW upgrade

examples/ts/signature-extension/package.json

@@ -4,7 +4,7 @@
   "type": "module",
   "scripts": {
     "build": "tsc",
-    "test": "../../../ts/npm-common-config/scripts/bash/npm-helpers/npm_download_browser_extensions.sh \"${HOME}/preinstalled_browser_extensions\" && ln -sf \"${HOME}/preinstalled_browser_extensions\" ./__tests__/extensions && playwright test --max-failures 1",
+    "test": "../../../ts/npm-common-config/scripts/bash/npm-helpers/npm_download_browser_extensions.sh \"${HOME}/preinstalled_browser_extensions\" && ln -sf \"${HOME}/preinstalled_browser_extensions\" ./__tests__/extensions && playwright install chromium && playwright test --max-failures 1",
     "test:manual": "parcel test/index.html"
   },
   "dependencies": {