HELSINKI (Reuters) -British Prime Minister Boris Johnson on Wednesday said he had agreed new deals with Sweden and Finland to bolster European security, pledging to support both countries’ armed forces should they come under attack. Johnson signed the new declarations, described by Britain as “a step-change in defence and security cooperation”, during visits to both Sweden and Finland on Wednesday. “What it says is that in the event of a disaster, or in the event of an attack on either of us, then we will come to each other’s assistance, including with military assistance,” Johnson said at a p…