By Carolyn Cohn and Lawrence White LONDON (Reuters) -Russia’s global financial isolation intensified on Friday as the London Stock Exchange (LSE) suspended trading in its last Russian securities and some insurers withdrew cover from exporters over Moscow’s invasion of Ukraine. Banks, investors and insurers have in recent days ratcheted up that pressure by exiting investments in Russia and halting the provision of their services. The LSE said it had suspended global depositary receipts (GDRs), which represent shares in a foreign company, for eight Russian companies, including Magnit and Sistema…