By Yimou Lee and Ben Blanchard TAIPEI (Reuters) – Taiwan President Tsai Ing-wen will pledge to bolster the island’s combat power and determination to improve its defences in a major speech on Monday, at a time when tensions with China have risen dramatically. Democratic Taiwan, claimed by China as its own territory, has come under increasing military and political pressure from Beijing, especially after Chinese war games in early August following a Taipei visit by U.S. House Speaker Nancy Pelosi. According to an outline of her national day speech on Monday, as described to Reuters by a source …