Fix an attitude transition bug in case of restart during transition

Fix for issue 552 : The "after" attitude law was deleted in case of restart of propagation during the transition period, and was not recomputed because the event was already in the past. The test was also incomplete because it ensured the validity of the transition attitude law but not the "after" attitude law in this precise case. Fix : added margins to the reset to keep both sides of the attitude transition, and add an "after" attitude law check in the test.