tests/e2e: increase delay before snapshot
tests/e2e: increase delay before snapshot

Increasing the delay before snapshots to prevent a failure in
the database-sql-driver when the nav takes too long to focus
on the current identifier.

Change-Id: If009f90c72c2f516d656f1a4ec3f55f8db9577f3
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/348935
Trust: Jamal Carvalho <e0195770807aa8c82b0b128d9c0423b5ad035172@golang.org>
Run-TryBot: Jamal Carvalho <e0195770807aa8c82b0b128d9c0423b5ad035172@golang.org>
TryBot-Result: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Jonathan Amsterdam <e3d3698b2ccd5955e4adf250d0785062d0f9018b@google.com>

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