Nope; head of state and head of government are still separate. All laws still require royal assent, the monarch still convenes and dissolves Parliament, and the monarch still has reserve powers (e.g. refusal of assent) although the leftists have bullied the monarchy into usually not using them. No foreign power recognizes the head of government as head of state, furthermore.
When other “heads of state” visit the UK, they meet with the PM, in this case, May. They don’t meet with the queen in order to work out “heads of state” stuff.