SYDNEY (Reuters) -Britain committed 25 million pounds ($34 million) to strengthen security in the Indo-Pacific as part of a pact with Australia, and leaders of both countries expressed “grave concerns” about China’s policies in its far western region of Xinjiang. In a video call on Thursday, British Prime Minister Boris Johnson and his Australian counterpart Scott Morrison also called for peace and stability across the Taiwan Strait and warned Russia against invading Ukraine. “They agreed the need for de-escalation and underscored that any further Russian incursion in Ukraine would be a massiv…