internal/frontend: add nonce to handleStaticPage
internal/frontend: add nonce to handleStaticPage

The nonce was removed from handleStaticPage in commit
806d23a163185c6a53903d9b6ae432b05d62206c in error (likely due to a merge
conflict issue) and is now added back.

Fixes b/137739555

Change-Id: I91d235cc7b40a8f5fbc2a053b8eccd2418e7c084
Reviewed-on: https://team-review.git.corp.google.com/c/golang/discovery/+/507996
Reviewed-by: Robert Findley <9179eee875d1ee628c37fb47d7e749e855ffd21f@google.com>

golang/pkgsite,golang/pkgsite,golang/pkgsite,golang/pkgsite