Bug 1775503 - [devtools] Prevent showing content process request when the...

Bug 1775503 - [devtools] Prevent showing content process request when the browser toolbox focuses on the parent process. r=bomsy

This is still one blind spot with privileged request done by content processes.
They aren't related to any BrowsingContext/WindowGlobal and there isn't any
attribute on channel/loadInfo which helps knowing they originates from a content process.

Differential Revision: https://phabricator.services.mozilla.com/D150014