[Extensions] Re-enable test CommandsApiTest.PageAction

chrome/test/data/extensions/api_test/keybinding/page_action/manifest.json

 {
-  "name": "A page action that makes the page red",
+  "name": "A page action that sends a 'clicked' test message",
   "version": "1.0",
   "manifest_version": 2,
   "background": {
     "scripts": ["background.js"]
   },
   "permissions": [
     "tabs", "http://*/*"
   ],
   "page_action": {
-    "default_title": "Make this page red",
+    "default_title": "Send message",
     "default_icon": "icon.png"
   },
   "commands": {
     "_execute_page_action": {
       "suggested_key": "Alt+Shift+F",
       "description": ""
     }
   }
 }