Log size of (un)partitioned SameSite=None cookies to UMA separately

This will help us compare the distribution of the size of cross-site
cookies that are partitioned or unpartitioned. This will give us some
insight into how people are using partitioned cookies versus
unpartitioned cookies.

Bug: 1448861
Change-Id: I158d00e99945e54ff49d3b38d98236b01affa938
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4567004


Reviewed-by: Chris Fredrickson <cfredric@chromium.org>
Commit-Queue: Dylan Cutler <dylancutler@google.com>
Cr-Commit-Position: refs/heads/main@{#1149378}