By Joanna Plucinska and Marek Strzelecki WARSAW (Reuters) -Russian energy giant Gazprom has told Poland and Bulgaria it will halt gas supplies from Wednesday, in a major escalation of Russia’s broader row with the West over its invasion of Ukraine. Poland and Bulgaria would be the first countries to have their gas cut off by Europe’s main supplier since Moscow started what it calls a military operation in Ukraine on Feb. 24. The move to cut off supplies also followed sanctions imposed by Warsaw against Russian individuals and companies. Russian President Vladimir Putin has demanded that countr…