updated initial value for OAUTH_APP_PASSWORD

The tutorial says:

> Replace YOUR APP ID HERE with the application ID from the Application Registration Portal, and replace YOUR APP SECRET HERE with the password you generated.

Author: enak

demo/graph-tutorial/.env.example

@@ -1,5 +1,5 @@
 OAUTH_APP_ID=YOUR_APP_ID_HERE
-OAUTH_APP_PASSWORD=YOUR_APP_PASSWORD_HERE
+OAUTH_APP_PASSWORD=YOUR APP SECRET HERE
 OAUTH_REDIRECT_URI=http://localhost:3000/auth/callback
 OAUTH_SCOPES='profile offline_access user.read calendars.read'
 OAUTH_AUTHORITY=https://login.microsoftonline.com/common/