[waffle]Change info dialog title from h1 to div

The `cr-dialog` element title slot is already an h2. We replace the h1
that we had by a div so that we only have one heading element when
using the screen reader.

Fixed: b:330931343, b:331561294
Change-Id: Iecba1af02b3d07712744df88d2eb0f7e087c3bb2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5397156


Reviewed-by: Nicolas Dossou-Gbété <dgn@chromium.org>
Commit-Queue: Nicolas Dossou-Gbété <dgn@chromium.org>
Auto-Submit: Jack Yammine <jyammine@google.com>
Cr-Commit-Position: refs/heads/main@{#1278986}