Add update string resources for productivity launcher

Adds strings for undo sort toast.
Changes strings for sorting cotext menu from Reorder by -> Sort by.
Updates continue section title.
Updates the dialog to remove an omnibox result.

BUG=None

Change-Id: Ib76797f176e63617e9083666383444ffcfcb7fd7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3437256
Reviewed-by: Andrew Xu <andrewxu@chromium.org>
Reviewed-by: Nancy Wang <nancylingwang@chromium.org>
Commit-Queue: Toni Barzic <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/main@{#967107}