fix #302316, fix #297501 - slurs and fingering

When a score, containing a fingering under a slur is loaded, the slur crosses the fingering.
Only after a relayout the slur is drawn higher so it won't intersect the fingering (issue

The root cause of this issue is the shapes of the fingering elements where not available
when the bezier of the slur is calculated. The fingering shapes are calculated after the
slur bezier is calculated. This explains why a relayout will solve the issue, then the
fingering shapes are available. The shapes are calculated during the calculation of the
note shapes but there was no call the fingering layout() method, making the bbox of
the fingering shape invalid and therefor it is not added.

This issue is solved by, in Score::layoutSystemElements(), calling the
Segment::createShapes() when layouting the fingering elements.

This solution also solves #302316 which also requires a relayout after a String Fingering
is added to note under a slur.

libmscore/layout.cpp

@@ -3765,6 +3765,7 @@ void Score::layoutSystemElements(System* system, LayoutContext& lc)
                                     }
                               }
                         }
+                  s->createShapes();
                   }
             }