CentralAuth is causing needless page/user invalidations.

Existing bad code paths:

• Title cache invalidation should be done only when email settings actually changed

LoginForm::execute
LoginForm::processLogin
LoginForm::authenticateUserData
CentralAuthPlugin::updateUser
User::saveSettings
Title::invalidateCache

• we should invalidate user cache only when there are changes that would need different rendering logic, not for every centralauthhooks session reload

User::getOption
User::loadOptions
User::load
User::loadFromSession
wfRunHooks
call_user_func_array
CentralAuthHooks::onUserLoadFromSession
CentralAuthHooks::initSession
User::invalidateCache

Version: unspecified
Severity: major