Show size of network request in Network tab

[johnpryan]

It would be helpful if the Network tab showed the size of the request and response in bytes. Right now, it only displays timing information:

[Victowolf]

Hi,
I worked on this issue and opened a PR to address it.

This PR adds support for displaying response size in the Network tab, including:

• A new "Size" column in the table
• Size row in the request inspector (Overview tab)

It uses socket byte metrics and HTTP content-length headers when available.

PR: #9744