[Flight] Log "Server Requests" Track (#33394)

Stacked on #33392.

This adds another track to the Performance Track called `"Server
Requests"`.

<img width="1015" alt="Screenshot 2025-06-01 at 12 02 14 AM"
src="https://github.com/user-attachments/assets/c4d164c4-cfdf-4e14-9a87-3f011f65fd20"
/>

This logs the flat list of I/O awaited on by Server Components. There
will be other views that are more focused on what data blocks a specific
Component or Suspense boundary but this is just the list of all the I/O
basically so you can get an overview of those waterfalls without the
noise of all the Component trees and rendering. It's similar to what the
"Network" track is on the client.

I've been going back and forth on what to call this track but I went
with `"Server Requests"` for now. The idea is that the name should
communicate that this is something that happens on the server and is a
pairing with the `"Server Components"` track. Although we don't use that
feature, since it's missing granularity, it's also similar to "Server
Timings".