By Elizabeth Pineau PARIS (Reuters) -Emmanuel Macron was expected to appoint a new prime minister on Tuesday, with 34-year-old Education Minister Gabriel Attal a favourite as the French President seeks to breathe new life into his second mandate ahead of European parliament elections. The move will not necessarily lead to any major political shift, but signals a desire for Macron to try to move beyond last year’s unpopular pension and immigration reforms and improve his centrist party’s chances in the June EU ballot. Opinion polls show Macron’s camp trailing far-right leader Marine Le Pen’s pa…