R1:2214f96d3fef

Fix some small notification / token issues

Summary:
Fixes T3218.

- Currently, Paste pages don't clear notifications about the paste (notably, token notifications).
- Currently, Paste pages don't show tooltips on tokens.
- `buildApplicationPage()` stopped respecting `pageObjects` (which controls whether "this page has been updated" is shown). Restore that.
- Make `pageObjects` imply "clear notifications on this stuff".

Test Plan: Viewed a tokened Paste. Verified it cleared the notification and…