The Camofox browser backend hardcoded a 30s HTTP timeout via
_DEFAULT_TIMEOUT, ignoring the user's browser.command_timeout config.
The main browser_tool path already reads this config via
_get_command_timeout().
This commit adds an equivalent _get_command_timeout() to
browser_camofox.py that reads browser.command_timeout from config
with caching, and switches all HTTP helper methods (_post, _get,
_get_raw, _delete) to use it as the default timeout.
Fixes#40843
