Access the options page when clicking the extension icon

Change-Id: I4dc518e1a828c79dcb86149c8213d72fff47fde5
diff --git a/templates/manifest.gjson b/templates/manifest.gjson
index b8ce324..2927deb 100644
--- a/templates/manifest.gjson
+++ b/templates/manifest.gjson
@@ -40,6 +40,7 @@
     "https://support.google.com/*/thread/*",
     "storage"
   ],
+  "browser_action": {},
 #if defined(CHROMIUM)
   "options_page": "options.html",
 #endif