Use span ver of network::ResourceRequestBody in ['content/browser/service_worker', 'content/renderer/service_worker']

...in preparation for removing the non-span versions. In many cases
this means the call now has "CopyOf" in the name; this denotes the copying
that was already taking place, it's just more explicit now.

This CL was uploaded by git cl split.

R=mek@chromium.org

Bug: 380211808
Change-Id: I9e9d3789f97d362a6d234a80ed4237f00a3b1df7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6039022
Auto-Submit: Maks Orlovich <morlovich@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1386929}